SSC San Diego TD 627 Revision D,
Annotated Bibliography of Publications from the U.S. Navy's Marine Mammal Program, May 1998


Anderson, L.N., A.R. Rasmussen, W.W.L. Au., P.E. Nachtigall, and H.L. Roitblat. 1994.Neural Network Modeling of a Dolphin’s Sonar Discrimination Capabilities. (Abs.). Jour. Acoust. Soc. Am. 96 (5, Pt. 2): 3316.

A previous modeling experiment used only spectral information of a dolphin’s echo. In this study, both time and frequency information were used to model the dolphin discrimination capabilities.

Adams, M. A., and P. E. Nachtigall. 1989. Chemical Communication in Dolphins: Chemical Constituents of the Perianal Gland (Abs.). 11th Annual Mtg., Assn. for Chemoreception Sciences (AChemS XI), Sarasota, FL. Chem. Senses 14 (5): 681.

Samples of perianal gland secretions were collected from male Tursiops. Combined gas chromatography-mass spectrometry analysis identified several long-chain organic acids in the samples. The possibility of chemically mediated behavior in dolphins is discussed.

Bello, M. A., R. R. Roy, T. P. Martin, H. W. Goforth, Jr., and V. R. Edgerton. 1985. Axial Musculature in the Dolphin (Tursiops truncatus): Some Architectural and Histochemical Characteristics. Marine Mammal Science 1: 324-336.

In view of reports that dolphins can swim faster than would be predicted based on physical features and presumed muscle power, this study examined muscle fiber types, fiber sizes and tendon arrangements of the dorsal and ventral axial muscles.

Briggs, M., W. Van Bonn, R. Linnehan, C. Messinger and S. Ridgway. 1995. Effects of Leuprolide Acetate in Depot Suspension on Testosterone Levels, Testicular Size and Semen Production in Male Atlantic Bottlenose Dolphins, Tursiops truncatus. 26th Annual Conf. of the International Association for Aquatic Animal Medicine, Mystic, CT, May 16-10, 1995, 26:112.

Leuprolide acetate (Leupron) was shown to be effective at reducing testosterone levels, testes size and sperm production in male bottlenose dolphins. Results of this study indicate Leupron may be a suitable method of chemical contraception in adult male dolphins.

Briggs, M.B., D. Messinger, C. Messinger, R.M. Linnehan, W. Van Bonn, S.H. Ridgway and W.G Miller. 1996. Effects of Leuprolide Acetate in Depot Suspension on Testosterone Levels, Testicular Size and Semen Production in Male Atlantic Bottlenose Dolphins (Tursiops truncatus). American Association of Zoo Veterinarians Conf., Puerto Vallarta, Mexico, Nov. 1996, pp. 330-331.

Paper describes the results of a study of GnRH analog use in dolphins.

Brown, W. R., J. R. Geraci, B. D. Hicks, D. J. St. Aubin, and J. P. Schroeder. 1983. Epidermal Cell Proliferation in the Bottlenosed Dolphin (Tursiops truncatus). Canadian Jour. Zool. 61: 1587-1590.

Using a radioactive labeling technique, the authors found that Tursiops has a large proliferative capacity which contributes to the unusual thickness of the skin.

Carder, D.A. and S.H. Ridgway. 1994. A Portable System for Physiological Assessment of Hearing in Marine Animals. Jour. Acoust. Soc. Am. 96 (5, Pt. 2): 3316.

Description of portable, stand-alone computer system for generating, digitizing and analyzing signals in the field.

Cartee, R.E., K. Broesmer and S.H. Ridgway. 1995. The Eye of the Bottlenose Dolphin (Tursiops truncatus) Evaluated by B-Mode Ultrasonography. Jour. Zoo.and Wildlife Medicine. 26 (3): 414-421.

The B-mode ultrasonographic images of bottlenose dolphin (Tursiops truncatus) eyes from cadavers and live animals were measured and compared with physical measurements of cadaver eyes. In live dolphins, eye diameters measured sonographically were not significantly different (2.55 cm x 2.32 cm) than either ultrasound or physical measurements. The optical axis diameter was 1.80 cm, and the circumference was 7.30 cm in live dolphins. Comparisons of circumference showed no significant difference between cadaver and live dolphin eye measurements.

Ceruti, M. G. 1983. Chemical Characteristics of Compounds Released by Marine Mammals. NOSC TR 930, 52 pp.

Excretions, secretions, and glandular extracts were analyzed to determine chemical constituents which may be involved in marine mammal chemoreception.

Ceruti, M. G., P. W. B. Moore, and S. A. Patterson. 1983. Peak Sound Pressure Level and Spectral Frequency Distributions in Echolocation Pulses of Atlantic Bottlenosed Dolphins (Tursiops truncatus). (Abs.) Jour. Acoust. Soc. Am. 74 (Suppl. 1): S73.

Peaks in the average bimodal pulse spectrum occurred at 60 and 135 kHz or beyond, while the average unimodal pulse spectrum peaked at 120 kHz. Abstract includes other findings.

Ceruti, M. G., P. V. Fennessey, and S. S. Tjoa. 1985. Chemoreceptively Active Compounds in Secretions, Excretions, and Tissue Extracts of Marine Mammals. Comp. Biochem. Physiol. 32A:505-514.

Hypothesizing that chemical communication may occur in marine mammals and that analysis of secretions and excretions would identify some specific compounds that might be involved, the authors determined the principal chemical components of sexual secretions, urine, feces, and blood from Atlantic Tursiops. Twenty-two identified compounds in aqueous solutions of sufficient concentration could be detected gustatorily by humans.

Colbert, A.A. 1996. Morphological Investigation of Variability in Bottlenose Dolphin (Tursiops truncatus) Skin for Use in Cutaneous Absorption Studies. Thesis, North Carolina State University, 92 pp.

Evaluates the morphological characteristics of Tursiops truncatus skin likely to impact dermal absorption kinetics to aid in the development of cutaneous absorption models to improve accuracy of evaluation of exposures to environmental contaminants.

Coulombe, H. N., S. H. Ridgway, and W. E. Evans. 1965. Respiratory Water Exchange in Two Species of Porpoise. Science 149: 86-88.

The exhalations of the two species of porpoises examined contained less water vapor than those of terrestrial mammals. This is seen as an adaptation to conserve water in these animals which live in an environment where no fresh water is available.

Davis, R.W. and T.M. Williams. 1992. Effect of Water Temperature on Swimming Energetics in Sea Lions. (Abs.) The Physiologist. 35 (4): 176.

Reports on study of the effect of water temperature on swimming metabolic rate. Decreasing water temperature resulted in 38% increase in resting oxygen consumption, but no significant difference in swimming oxygen consumption. Results show energetic cost of swimming in sea lions is independent of water temperature between 5 and 30 deg. C.

Dawson, W. W., D. A. Carder, S. H. Ridgway, and E. T. Schmeisser. 1981. Synchrony of Dolphin Eye Movements and Their Power Density Spectra. Comp. Biochem. Physiol. 68A:443-449.

Eye movements in the horizontal and vertical planes of a normal human and two bottlenosed dolphins were analyzed and compared. Although dolphin eyes are mobile at lower fundamental frequencies than in humans, there is a low level of synchrony between the two eyes.

Dawson, W. W., J. P. Schroeder, and J. F. Dawson. 1987. The Ocular Fundus of Two Cetaceans. Marine Mammal Science. 3:1-13.

By use of a technique to correct the aerial myopia encountered in fundus photography of the marine mammal eye, the first high quality photographs were obtained of the eyes of a living Tursiops and a Grampus.

Dawson, W. W., J. P. Schroeder, and S. N. Sharpe. 1987. Corneal Surface Properties of Two Marine Mammal Species. Marine Mammal Science. 3:186-197.

Describes and compares the cornea of Tursiops and Zalophus. The results provide an explanation for the resolution of the Zalophus eye in air and water, but "the aerial acuity of Tursiops remains a mystery."

Dawson, W. W., P. E. Nachtigall, J. C. Dawson, G. M. Hope, and J. P. Schroeder. 1992. Cetacean Lens-Zones of Discontinuity-Indices of Health and Development. Marine Mammal Science. 8 (4): 379-386.

Details of the eye lenses of two living bottlenose dolphins (Tursiops truncatus) and a Risso’s dolphin (Grampus griseus) were photographed. Spatially periodic stria could be visualized, with varying spaces between stria. Digitization of one photo allowed quantification of sizes and numbers of layers. Lens zone measurement may provide data on cetacean health and age.

Dawson, W. W., J. P. Schroeder, J. C. Dawson, and P. E. Nachtigall. 1992. Cyclic Ocular Hypertension in Cetaceans. Marine Mammal Science. 8 (2): 135-142.

Intraocular pressure (IOP) was measured in each eye of two adult Tursiops truncatus and one Grampus griseus. Measurements were made in alternation between eyes over a time span. Compared to humans, these cetaceans exhibit clinical ocular hypertension bilaterally. The range of pressures found, over time, was much greater than reported previously for several terrestrial mammals.

Demski, L. S., S. H. Ridgway, T. H. Bullock, and M. Schwanzel-Fukuda. 1985. Terminal Nerve of Odontocete Whales. Amer. Zool. 25:107A.

See Ridgway et al., 1987, below.

Demski, L. S., S. H. Ridgway, and M. Schwanzel-Fukuda. 1990. The Terminal Nerve of Dolphins: Gross Structure, Histology and Lutenizing-Hormone-Releasing Hormone Immunocytochemistry. Brain, Behavior and Evolution. 36:249-261.

The structure and cell type of the dolphin terminal nerves and ganglion are described. The cells that exhibit a response to lutenizing hormone releasing hormone antibody are figured and described in detail.

Dolphin, W.F., W.W.L. Au, P.E. Nachtigall, and J.L. Pawloski. 1995. Modulation Rate Transfer Functions to Low Frequency Carriers by Three Species of Cetaceans. Jour. Comp. Physiol. 177: 235-245.

Modulation rate transfer functions were obtained from a false killer whale (Pseudorca crassidens), a beluga whale (Delphinapterus leucas) and a bottlenose dolphin (Tursiops truncatus) in a study of their auditory capabilities employing electrophysiological techniques. The vast majority of previous studies in this area employed psychophysical techniques.

Duffield, D. A., S. H. Ridgway, and R. S. Sparkes. 1967. Cytogenetic Studies of Two Species of Porpoise. Nature 213:189-190.

The diploid chromosome number for a male and female Tursiops truncatus and for two males and one female Lagenorhynchus obliquidens was found to be 44. There were no obvious differences in the karyotypes of the two species.

Duffield, D. A., S. H. Ridgway, and L. H. Cornell. 1983. Hematology Distinguishes Coast and Offshore Forms of Dolphins (Tursiops). Can. Jour. Zool. 61: 930-933.

Bottlenosed dolphins can be separated into coastal and offshore ecotypes based on hematologic values, the offshore forms having higher values. There appears to be a significant genetic basis for these differences.

Flanigan, N. J. 1965. Neuroanatomy of the Dolphin Spinal Cord. Anat. Rec. 151:350.

Flanigan, N. J. 1966. The Anatomy of the Spinal Cord of the Pacific Whitesided Dolphin (Langenorhynchus obliquidens). In: Whales, Dolphins. and Porpoises, K.S. Norris (ed.). Univ. of Calif. Press, Berkeley, pp. 207-231.

Describes the anatomy of the spinal cord and discusses the possible significance of its distinctive features.

Flanigan, N. J. 1972. The Central Nervous System. In: Mammals of the Sea -Biology and Medicine, S. H. Ridgway (ed.). Chas. C. Thomas Publ., Springfield, IL, pp. 215-246.

Reviews present knowledge of the central nervous system of cetaceans and pinnipeds, including findings made by the author while working at the Navy’s Marine Bioscience Facility.

Fong, M. L., R. M. Yamada, and W. A. Friedl. 1989. Post Exercise Skin Temperature and Heat Flux of Atlantic Bottlenosed Dolphins (Tursiops truncatus). (Abs.) Eighth Biennial Conf. on the Biology of Marine Mammals. Society of Marine Mammalogy, Pacific Grove, CA., p. 20.

Skin temperatures and heat flux were measured from two dolphins before and after controlled swimming. Different temperature and flux patterns occurred for the dolphins’ bodies and fins.

Friedl, W. A., R. M. Yamada, M. L. Fong, and J. E. Haun. 1987. Physical Conditioning of Bottlenosed Dolphins for Bioenergetic Studies. (Abs.) Seventh Biennial Conf. on the Biology of Marine Mammals, Society of Marine Mammalogy, Miami, FL, p. 23.

Describes the equipment, training, and conditioning regime for a study to determine dolphin aerobic work capacity and swimming energy requirements.

Friedl, W. A., J. E. Haun, M. L. Fong, and R. M. Yamada. 1989. Aerobic Exercise by Bottlenosed Dolphins. (Abs.) Eighth Biennial Conf. on the Biology of Marine Mammals. Society of Marine Mammalogy, Pacific Grove, CA., p. 21.

Describes measurements of oxygen consumption and respiration rate for aerobic exercise at controlled levels. Results indicated short-term oxygen debts were incurred even for conditions seemingly within the dolphins’ maximal aerobic capacity.

Friedl, W. A., P. E. Nachtigall, P. W. B. Moore, N. K. W. Chun, J. E. Haun, R. W. Hall, and J. L. Richards. 1990. Taste Reception in the Pacific Bottlenosed Dolphin (Tursiops truncatus gilli) and the California Sea Lion (Zalophus californianus). In: Sensory Abilities of Cetaceans, J. A. Thomas and R. A. Kastelein (eds.). Plenum Press, New York, pp. 447-454.

Abilities to detect sour, bitter, salty, and sweet substances in distilled water were tested. The dolphin detected all four tastes. The sea lion detected salty, sour and some bitter substances but not other bitter tastes or the sweet taste (sucrose). The study showed for the first time that bottlenosed dolphins can detect sweet substances and that California sea lions have gustatory senses.

Gilmartin, W. G., R. W. Pierce, and G. A. Antonelis, Jr. 1974. Some Physiological Parameters of the Blood of the California Gray Whale. Mar. Fish. Rev. 36 (4):28-31.

Hematocrit, oxyhemoglobin dissociation curve, and blood volume were determined, the last by isotopic techniques.

Green, R. F. 1972. Observations on the Anatomy of Some Cetaceans and Pinnipeds. In: Mammals of the Sea -Biology and Medicine, S. H. Ridgway (ed.). Chas. C. Thomas Publ., Springfield, IL, pp. 247-297.

Observations (with unique new illustrations) of cetacean and pinniped anatomy based primarily on dissections made by the author.

Greenwood, A. G., S. H. Ridgway, and R. J. Harrison. 1971. Blood Values in Young Gray Seals. Jour. Am. Vet. Med. Assn. 159 (5):571-574.

Red and white blood cell measurements, plasma electrolytes and serum proteins, and blood chemistry values are given.

Hamlin, R. L., S. H. Ridgway, and W. G. Gilmartin. 1972. Electrocardiogram of Pinnipeds. Am. Jour. Vet. Res. 33(4):867-875.

Electrocardiograms obtained from California sea lions, elephant seals, and harbor seal are analyzed and discussed.

Harrison, R. J., and S. H. Ridgway, 1971. Gonadal activity in some bottlenosed dolphins (Tursiops truncatus). Jour. Zool. 165:355-366.

Characteristics of the ovaries and testes of young and adult bottlenosed dolphins indicate that sexual maturity in females is probably reached in their fifth year. Males become sexually mature at an estimated age of 10 years. No evidence of regular cyclic ovulation was found.

Harrison, R. J., and S. H. Ridgway. 1975. Restrained and Unrestrained Diving in Seals. Rapp. P. -v. Reun. Cons. Int. Explor. Mer. 169:76-80.

Cardiovascular response of gray seals was much higher during a forced dive than during an unrestrained trained dive. Cardiac rhythm also varied with different observed behaviors.

Harrison, R. J., and S. H. Ridgway. 1976. Deep Diving Mammals. 51 pp. Meadowfield Press Ltd., Durham, England.

A booklet reviewing what is known about deep diving in mammals, including depth and duration of dives, historical background, adaptations, other aspects of deep diving, and future deep diving by man.

Heath, M.E. and W.G. Miller. 1997. Physiological Responses to Encountering Warm Water in Bottlenose Dolphins. Experimental Biology Conf., New Orleans, LA, April 1997.

Study showed dolphins appear to have a highly adapted mechanism enabling the animal to redistribute body heat to the blubber layer resulting in a lower core temperature when exposed to warm water. This adaptation reduces the rate of heat gained from the environment and provides a margin of safety in the level of core temperature for dolphins encountering warm water conditions that may pose a heat stress.

Horvath. S. M., H. Chiodi, S. H. Ridgway, and S. Azar, Jr. 1968. Respiratory and Electrophoretic Characteristics of Hemoglobin of Porpoises and Sea Lions. Comp. Biochem. Physiol. 24:1027-1033.

Porpoises that swim faster and dive longer and deeper have greater hemoglobin oxygen affinity than the slower swimming, shallower, and shorter diving species.

Hui, C. A., 1975. Thoracic Collapse as Affected by the Retia Thoracica in the Dolphin. Resp. Physiol. 25:63-70 (Netherlands).

The carcass of a Delphinus was subjected to two simulated dives in a hyperbaric chamber to the equivalent of 69.7 m. In one dive, the thorax was in natural state; in the other, 100 ml. of water had been injected into each pleural cavity. Results indicated that an engorged thoracicrete reduced the displacement stress on abdominal organs under pressures encountered in diving.

Hui, C. A. 1978. Reliability of Using Dentin Layers for Age Determination in Tursiops truncatus. A report to the Marine Mammal Commission. Nat’l Tech. Info. Serv. PB-288 444, 25 pp.

Discusses histology of the mammalian tooth, utility of using dentin layers for age determination, and findings from an examination of teeth from three Tursiops, two of known age. It is concluded that annual increments of dentin are visible and can be regular through 11 years. No correlation of dentin layering with food consumption patterns or innate biorhythms based on lunar cycles was found.

Hui, C. A. 1979. Correlates of Maturity in the Common Dolphin (Delphinus delphis). Fish. Bull. 77:295-300.

Body weight and length, degree of bone fusion in flippers, dentine layers, testes weights, and ovarian scars in 87 D. delphis (which had died in tuna nets) were treated statistically to determine correlation with sexual maturity.

Hui, C. A. 1981. Seawater Consumption and Water Flux in the Common Dolphin (Delphinus delphis). Physiol. Zool. 54 (4) :430--440.

In two captive dolphins, total body water was found to be low (37 percent of total body weight), indicating a high fractional rate of water turnover, most of which is due to the permeability of the skin. Skin was shown to be impermeable to sodium, so the only sodium source is ingested sea water.

Jensen, E., W. Van Bonn, M. Beeler and S. Ridgway. 1995. Forestomach Acidity of Tursiops truncatus. 11th Biennial Conf. on the Biology of Marine Mammals, Orlando, FL, Dec. 14-18, p. 59.

Paper presenting normal forestomach acidity in pre- and post-prandial dolphins.

Kanwisher, J. W., and S. H. Ridgway. 1983. The Physiological Ecology of Whales and Porpoises. Sci. Am. 248 (6):110-120.

Discusses the particular physiologic adaptations evolved by cetaceans for living in the sea, notably the ability to dive deep for long periods. Unlike other marine organisms, which tend to move nutrients downward, oceanic marine mammals, through their fecal output near the surface, tend to move nutrients upward.

Ketten, D.R., J. Lien, S. Todd and S. Ridgway. 1994. Acoustic Damage in Whale Ears: Aging vs. Injury. The Physiologist. 37 (5): 10.1.

Cochlear structure of an old dolphin with hearing loss was analyzed for potential use as a model to reveal hearing loss in stranded animals.

Ketten, D.R., S. Ridgway and G. Early. 1995. Apocalyptic Hearing: Aging, Injury, Disease, and Noise in Marine Mammal Ears. 11th Biennial Conf. on the Biology of Marine Mammals, Orlando, FL, Dec. 14-18, p. 94.

Describes work to correlate changes in marine mammal ear anatomy as a result of age, biological factors and noise.

Kulu, D. D., I. Veomett, and R. S. Sparkes. 1971. Cytogenetic Comparison of Four Species of Cetaceans. Jour. Mammal. 52 (4): 828-832.

The model chromosome number for the common dolphin, Amazon freshwater dolphin, Dall’s porpoise, and killer whale is 44, the same as that in other cetaceans examined, with the exception of the sperm whale, which has 42. Karyotypes of the killer and sperm whales are otherwise similar. The possible significance of these findings is discussed.

Leatherwood, J. S., M. W. Deerman, and C. W. Potter. 1978. Food and Reproductive Status of Nine Tursiops truncatus from the Northeastern United States Coast. Cetology, No. 28, 6 pp.

The nine dolphins (six stranded, three entangled in a fishing net) were examined for age, reproductive status, and stomach contents. Stomachs contained a predominance of Atlantic croakers, sea trout, and spot.

Lowell, W. R., and W. F. Flanigan, Jr. 1978. Chemoreception in Marine Mammals: A Review of the Literature. NOSC TR 353, 19 pp.

Discusses anatomical and physiological correlates and behavioral and ecological considerations of olfaction and gustation in cetaceans, pinnipeds, sea otters, and sirenians, followed by a bibliography.

Lowell, W.R. and W.F. Flanigan, Jr. 1980. Marine Mammal Chemoreception. Mammal. Rev., 1980:1053-1059.

Later version of previous publication.

Malvin, R. L., J. P. Bonjous, and S. H. Ridgway. 1971. Antidiuretic Hormone Levels in Some Cetaceans. Soc. Exp. Biol. and Med. 136 (4):1203-1205.

Data on renal function in the bottlenosed dolphin and killer whale are presented and discussed.

Malvin, R. L., S. H. Ridgway, and L. Cornell. 1978. Renin and Aldosterone Levels in Dolphins and Sea Lions. Soc. Exper. Biol. and Med. 157:665-668.

A significant correlation between plasma renin activity (PRA) and concentration of aldosterone in plasma was found in both dolphins and sea lions. An excellent correlation between urinary sodium excretion and PRA was also obtained in two dolphins. These data support the hypothesis that in marine mammals the reninangiotensionaldosterone axis plays a role in the regulation of salt balance.

McCormick, J. G., E. G. Wever, J. L. Mattsson, and S. H. Ridgway. 1977. Anatomical and Physiological Adaptations of Marine Mammals for the Prevention of Diving induced Middle-ear Barotrauma and Round Window Fistula. Undersea Biomedical Research 4 (1): A 42.

Comparative marine mammal experience helped make a preoperative diagnosis of diving-induced round window fistula in a human patient.

Nachtigall, P. E., and R. W. Hall. 1984. Taste Reception in the Bottlenosed Dolphin. Acta Zoo. Fennica 172:147-148.

A dolphin’s taste thresholds for citric acid (sour) and quinine sulfate (bitter) were found to be just above the human thresholds for these substances.

Nachtigall, P. E. 1986. Vision, Audition, and Chemoreception in Dolphins and Other Marine Mammals. In: Dolphin Cognition and Behavior, R. J. Schusterman, J. A. Thomas, and F. G. Wood (eds.). Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 79-113.

A review of what is known about sensory capabilities in dolphins, pinnipeds, and sea otters (vision only).

Nachtigall, P. E. 1989. Risso’s Dolphin (Grampus griseus) Vision. (Abs.) Eighth Biennial Conf. on the Biology of Marine Mammals, Society of Marine Mammalogy, Pacific Grove, CA., p. 45.

See Nachtigall, 1989, below.

Nachtigall, P. E. 1989. Visual Acuity of the Risso’s Dolphin (Grampus griseus) in Air. (Abs.) Bulletin of the Psychonomic Society 27 (6):502.

Visual acuity, in terms of minimum angle of resolution, was measured using a two-alternative forced-choice procedure.

Nachtigall, P. E., and J. L. Pawloski. 1991. Aerial Visual Acuity of the Risso’s Dolphin at Two Distances. (Abs.) Bulletin of the Psychonomic Society 29 (6):528.

Visual acuity, in terms of minimum angle of resolution, was measured at distances of 1 and 2.5 meters. Resolution was found to be better at 2.5 meters than at 1 meter.

Pabst, D.A., S.A. Rommel, W.A. McLellan, T.M. Williams and T.K. Rowles. 1995. Thermoregulation of the Intra-Abdominal Testes of the Bottlenose Dolphin (Tursiops truncatus) During Exercise. Jour. Exp. Biology. 198: 221-226.

A special rectal probe measured colonic temperatures simultaneously before and immediately after vigorous swimming. The results suggested the dolphin’s countercurrent heat exchanger has an increased ability to cool arterial blood supply to the testes during swimming. Believed to be first report of deep body cooling in an exercising mammal that is not diving.

Pepper, R. L., and J. V. Simmons, Jr. 1973. In-air Visual Acuity of the Bottlenosed Dolphin. Exper. Neur. 41 (2):271-276.

Horizontal-black and white-line gratings were presented in a successive discrimination task. Over a constant viewing distance of 2.8 meters, a minimal visual angle of 18 minutes of arc was obtained.

Ridgway, S. H., and D. G. Johnston. 1966. Blood Oxygen and Ecology of Porpoises of Three Genera. Science 151 (3709):456--458.

The total blood-oxygen content of the highly active, deep-diving Dall’s porpoise is almost three times that of the coastal dwelling bottlenosed. The pelagic white-sided dolphin, less active than the Dall, is intermediate. Heart weight of the Dall’s porpoise is about 140 percent that of the bottlenosed.

Ridgway, S. H., B. L. Scronce, and J. Kanwisher. 1969. Respiration and Deep Diving in the Bottlenosed Porpoise. Science 166:1651-1654.

A porpoise was trained to dive on command to depths down to 300 meters, then provide a lung air sample at the surface before breathing. It was also trained to swim between divers at 20 meters and to breath-hold at the surface for deep-dive time equivalents. Analyses of oxygen and carbon dioxide were then compared for the three situations.

Ridgway, S. H., J. G. Simpson, G. S. Patton, and W. G. Gilmartin. 1970. Hematologic Findings in Certain Small Cetaceans. Jour. Am. Vet. Med. Assn. 157:566-575.

Clinical laboratory data on the blood of small cetaceans were collected from representatives of a number of species.

Ridgway, S. H. 1971. Buoyancy Regulation in Deep Diving Whales. Nature 232 (5306): 133-134.

Comments on a suggestion that the spermaceti organ of sperm whales serves as a buoyancy regulator in deep dives. Evidence is presented that this hypothesis is incorrect.

Ridgway, S. H., and G. S. Patton. 1971. Dolphin Thyroid: Some Anatomical and Physiological Findings. Z. vergl. Physiol. 71:129-141.

Research conducted with representatives of four species of delphinids was directed toward elucidating the function of this organ in toothed cetaceans. Biochemical data on thyroid hormones are presented. All animals examined had larger thyroids than terrestrial mammals of comparable weight.

Ridgway, S. H. 1972. Homeostasis in the Aquatic Environment. In: Mammals of the Sea - Biology and Medicine, S. H. Ridgway (ed.). Chas. C. Thomas Publ., Springfield, FL, pp. 590-747.

Account of marine mammal research conducted by the author in the areas of diving physiology, water balance, reproductive physiology, hematology, and blood chemistry, husbandry, behavior, and animal health (including anesthesia).

Ridgway, S. H. 1973. Control Mechanisms in Diving Dolphins and Seals. Doctoral Thesis, University of Cambridge, 90 pp. with appendices.

Primarily on diving physiology of dolphins, sea lions, and seals (especially the gray seal), but also includes research on hearing, sleep, and brain temperatures in the gray seal.

Ridgway, S. H., J. G. McCormick, and E. G. Wever. 1974. Surgical Approach to the Dolphin’s Ear. Jour. Exp. Pathol. 188 (3):265-276.

Describes anesthesia procedure, surgical techniques, and physiological monitoring for making electrophysiological measurements at the cochlea.

Ridgway, S. H., D. A. Carder, and W. Clark. 1975. Conditioned Bradicardia in the Sea Lion (Zalophus californianus). Nature 256 (5512):37-38.

Slowing of heart rate was achieved by conventional conditioning techniques.

Ridgway, S. H. 1976. Diving Mammals and Biomedical Research. Oceanus 19 (2):49-55.

Describes biomedical research conducted with the California sea lion, gray seal, common seal, elephant seal, Weddell seal, and bottlenosed dolphin.

Ridgway, S. H., and R. H. Brownson. 1979. Brain Size and Symmetry in Three Dolphin Genera. Anat. Rec. 193:664.

Asymmetries of weight and surface area of cerebral cortex between right and left hemispheres were found in Tursiops and Delphinus, but no significant asymmetries were found in Stenella. Average body and brain weights, lengths, and cortical surface areas are given for 13 Tursiops, 9 Delphinus, and 11 Stenella.

Ridgway, S. H., and R. Howard. 1979. Dolphin Lung Collapse and Intramuscular Circulation During Free Diving: Evidence from Nitrogen Washout. Science 206:1182-1183.

Intramuscular nitrogen tensions in Tursiops after repetitive ocean dives suggested that lung collapse occurs at a depth of about 70 meters and that intramuscular circulation is maintained during unrestrained diving in the open sea. The dolphin is not protected by lung collapse in dives shallower than 70 meters.

Ridgway, S. H., T. H. Bullock, D. A. Carder, R. L. Seeley, D. Woods, and R. Galambos. 1981. Auditory Brainstem Responses in Dolphins. Proc. Natl. Acad. Sci. 78 (3):1943-1947.

Auditory brainstem response (ABR) in two Tursiops and two Delphinus were compared with human and rat ABR data. The ABR can be used to test theories of dolphin sonar signal processing and permits rapid evaluation of hearing thresholds. Audiometric information on stranded or trapped giant whales might be obtained by using the ABR.

Ridgway, S. H., and C. A. Fenner. 1982. Weight-Length Relationships of Wild-Caught and Captive Atlantic Bottlenosed Dolphins. Jour. Am. Vet. Med. Assn. 181 (11):1310-1315.

From weight and length measurements of 144 dolphins, guidelines were established for use in estimating whether a dolphin is over or underweight.

Ridgway, S. H., C. A. Bowers, D. Miller, M. L. Schultz, C. A. Jacobs, and C. A. Dooley. 1984. Diving and Blood Oxygen in the White Whale. Canadian Jour. Zool. 62 (11): 2349-2351.

White whales, trained to dive on command in the open sea, remained submerged as long as 15 minutes 50 seconds and dove as deep as 647 meters (2122 feet).

Ridgway, S. H., and R. H. Brownson. 1984. Relative Brain Sizes and Cortical Surface Areas in Odontocetes. Acta Zool. Fennica 172:149-152.

Surface area of the cerebral cortex was found to be directly related to brain weight in a variety of odontocetes, but the genera differed greatly when cortical area and brain weight were related to body length and weight and to encephalization quotient. Includes findings on brains of neonates and on brain asymmetries.

Ridgway, S. H. 1985. The Bends Problem: Dolphins, Seals, and Nitrogen. (Abs.) Sixth Biennial Conf. on Biology of Marine Mammals, Society of Marine Mammalogy, Vancouver, B. C., Canada, Nov. 22-26, p. 102.

Reviews and compares findings from diving studies on dolphins and seals. Dolphin breath-hold time is shorter, but they dive faster and seem capable of more deep dives in rapid succession.

Ridgway, S. H. 1986. Diving Responses. Letter to the Editor: Reply to R. Elsner. Marine Mammal Science 2 (4):326-328.

Discusses the so-called "diving responses." Proposes more specific terminology for the physiological processes involved.

Ridgway, S. H. 1986. Diving Dolphins. In: Research on Dolphins, M. M. Bryden and Richard Harrison (eds.). Oxford Univ. Press, New York, pp.33-58.

Includes historical background on depth-of-dive inferences and observations, modern studies, hazards of diving, respiration, bradycardia, and species differences with respect to metabolism, blood volume, and blood oxygen capacity.

Ridgway, S. H. 1986. Dolphin Brain Size. In: Research on Dolphins, M. M. Bryden and R. J. Harrison (eds.). Oxford Univ. Press, New York, pp. 59-70.

Discusses absolute brain sizes in cetaceans; the various cephalization coefficient concepts, including Jerison’s "encephalization quotient," here applied to cetaceans; growth of the brain; fissurization; volume of the dolphin cortex; and asymmetry of the dolphin brain.

Ridgway, S. H. 1986. Physiological Observations on Dolphin Brains. In: Dolphin Cognition and Behavior, R. J. Schusterman, J. A. Thomas, and F. G. Wood (eds.). Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 31-59.

Discusses anatomical and physiological characteristics of dolphin brains, including size, convolutedness, cortex volume, metabolism, hemispheric independence, lateralization, and auditory areas.

Ridgway, S. H. 1986. Diving in Cetaceans. In: Diving in Animals and Man, A.O. Brubakk, J. W. Kanwisher, and G. Sundness (eds.). The Norwegian Society of Science and Letters, Trondheim, Norway, pp. 33-62.

A comprehensive account, including known diving capabilities of 10 cetaceans, techniques used to study diving, physiological and anatomical hazards of diving, adaptations for diving, sound production and diving, metabolism and diving, oxygen stores, and bradycardia.

Ridgway, S.H. 1987. The Cetacean Central Nervous System. In: Encyclopedia of Neuroscience, Vol. I, G. Adelman (ed.). Birkhauser, Boston, pp.220-225.

The author writes a concise review of what is known about the cetacean central nervous system with special emphasis on anatomy and physiology.

Ridgway, S. H., L. S. Demski, T. H. Bullock, and M. Schwanzel-Fukuda. 1987. The Terminal Nerve in Odontocete Cetaceans. Ann. New York Acad. Sci. 519:201-212.

Terminal nerves accompany olfactory nerves in many vertebrate species. Olfactory nerves are completely absent, however, in adult odontocetes, but large, myelinated terminal nerves persist. Five odontocete species were studied in detail; the terminal nerves observed were the largest ever reported. The possible chemosensory function of the terminal nerve in odontocetes is discussed.

Ridgway, S. H. 1988. The Cetacean Central Nervous System. In: Comp. Neuroscience and Neurobiology. Birkhauser, Boston 1:20-25.

Current knowledge on the anatomy and physiology of the central nervous system of whales, dolphins, and porpoises is reviewed.

Ridgway, S. H., and F. G. Wood. 1988. Cetacean Brain Evolution. Behav. and Brain Sci. 11 (1): 99-100.

Comment on review article. Presents facts on absolute and relative sizes of cetacean brains. Discusses evolutionary aspects of cetacean brain development and cites relevant literature.

Ridgway, S. H. 1989. The Central Nervous System of the Bottlenosed Dolphin. In: The Bottlenosed Dolphin, Tursiops spp., J. S. Leatherwood and R. Reeves (eds.). Academic Press, San Diego, CA, pp. 69-97.

Current knowledge on the brain of the bottlenosed dolphin (Tursiops truncatus) is reviewed. Photographs and drawings illustrate various features of the brain.

Ridgway, S. H., and D. A. Carder. 1990. Tactile Sensitivity, Somatosensory Responses, Skin Vibrations, and the Skin Surface Ridges of the Bottlenosed Dolphin (Tursiops truncatus). In: Sensory Abilities of Cetaceans, J. A. Thomas and R. A. Kastelein (eds.). Plenum Press, New York, pp. 163-179.

The dolphin’s skin sensitivity was studied through the use of electrophysiological techniques. A map of skin sensitivity is presented and skin anatomy is discussed with special consideration of the cutaneous ridges and muscle underlying the skin.

Ridgway, S., M. Reddy, T. Kamolnick, D. Skaar and C. Curry. 1992. Calorie Consumption of Growing Adult, Pregnant, and Lactating Tursiops. 23rd Annual Conf. of the International Association for Aquatic Animal Medicine, Hong Kong, May 18-22, 1992, 23: 44.

Calorie consumption required for Tursiops truncatus at various stages of life were measured and presented along with graphs showing the reduction in calorie consumption as the dolphin ages.

Ridgway, S.H., T. Kamolnick, M. Reddy, and C. Curry. 1993. Relactation by 30+ year-old Tursiops After Suckling by Unrelated Orphan Calves. 24th Annual Conf. of the International Association for Aquatic Animal Medicine. Chicago, IL, May 16-20, 24:105.

Report of two cases where suckling by unrelated calves resulted in milk production in two mature female bottlenose dolphins, Tursiops truncatus.

Ridgway, S.H. and R.J. Tarpley. 1995. Brain Mass Comparisons in Cetacea. Society for Neuroscience. 21 (1):433.

Presents data on more than 1000 cetacean brains. Different groups are compared, showing that the largest brains are found among the family Delphinidae.

Ridgway, S.H. and S. Kohin. 1995. The Relationship Between Heart Mass and Body Mass for Three Cetacean Genera: Narrow Allometry Demonstrates Interspecific Differences. Marine Mammal Science. 11 (1):72-80.

A narrow scale allometric analysis demonstrated significant differences in the scaling of heart mass with body mass in three cetacean genera--Phocoenoides dalli, Lagenorhynchus obliquidens and Tursiops truncatus--that may be due to differences in physiologic and ecological demands.

Ridgway, S.H. and R.J. Tarpley. 1996. Brain Mass Comparisons in Cetacea. 27th Annual Conf. of the International Association for Aquatic Animal Medicine, Chattanooga, TN, May 11-15. 27:55.

See Ridgway and Tarpley, 1995, above.

Romano, T. and D.L. Felten. 1988. Neural-Immune Interactions--A Potential Area of Investigation for Marine Mammals. 19th Annual Conf. of the International Association for Aquatic Animal Medicine, Baltimore, May 22-26, 1988, 19:68.

Discusses potential application of neural-immune interactions to marine mammals.

Romano, T., D.L. Felten and J.A. Olschowka. 1989. Neural-Immune Interactions in the Beluga Whale. 20th Annual Conf. of the International Association for Aquatic Animal Medicine, San Antonio, TX, May 14-19, 1989, 20:82.

Demonstrates anatomical pathways linking the nervous and immune systems in the beluga.

Romano, T., D.L. Felten, J.A. Olschowka and S.Y. Felten. 1991. The Demonstration of a Possible Link for Neural-Immune System Interactions in the Beluga Whale. (Abs.) Society of Neuroscience Abstracts. 17 (1):833.

Demonstrates innervation of white whale or beluga lymphoid organs such as spleen, lymph nodes and thymus.

Romano, T., J.A. Olschowka, S.Y. Felten, and D.L. Felten. 1991. Neural-Immune Interactions in the Beluga Whale. (Abs.) Society of Neuroscience Abstracts. 17 (1):833.

Discusses the interaction of the nervous and immune systems in the beluga whale.

Romano, T., J.A. Olschowka, S.Y. Felten and D.L. Felten. 1992. Communication of Nervous and Immune Systems in the Beluga, Delphinapterus leucas. 23rd Annual Conf. of the International Association for Aquatic Animal Medicine, Hong Kong, May 18-22, 1992, 23:97.

Discusses neural-immune interactions in the beluga.

Romano, T.A., S.H. Ridgway and V. Quaranta. 1992. MHC Class II Molecules and Immunoglobulins on Peripheral Blood Lymphocytes of the Bottlenosed Dolphin, Tursiops truncatus. Jour. Exper. Zoology. 263: 96-104.

Describes the distribution of class II molecules and surface immunoglobulins on dolphin peripheral blood lymphocytes.

Romano, T.A., S.Y. Felten, J.A. Olschowka and D.L. Felten. 1993. A Microscopic Investigation of the Lymphoid Organs of the Beluga, Delphinapterus leucas. Jour. Morphology. 215:261-287.

Investigates morphology of white whale or beluga lymphoid organs. This is the first ever comprehensive description of lymphoid organs from the white whale.

Romano, T., S.Y. Felten, J.A. Olschowka and D.L. Felten. 1993. General Morphology and Innervation of the Lymphoid Organs in the Beluga, Delphinapterus leucas. 24th Annual Conf. of the International Association for Aquatic Animal Medicine, Chicago, IL, May 16-20, 24:111.

Discusses the morphology and innervation of white whale or beluga lymphoid organs such as spleen, lymph nodes and thymus.

Romano, T., D.L. Felten, S.Y. Felten and J.A. Olschowka. 1993. An Anatomical Link Between the Nervous and Immune Systems in the Beluga, Delphinapterus leucas. Tenth Biennial Conf. on the Biology of Marine Mammals, Galveston, TX, Nov. 11-15, 1993, p. 6.

Investigates neural-immune interactions in the white whale or beluga, with special reference to the anatomy of the nervous system and organs involved in the immune system.

Romano, T.A., S.Y. Felten, J.A. Olschowka and D.L. Felten. 1994. Noradrenic and Peptidergic Innervation of Lymphoid Organs in the Beluga, Delphinapterus leucas: An Anatomical Link Between the Nervous and Immune Systems. Jour. Morphology. 21:243-259.

Investigates the innervation of the white whale or beluga lymphoid organs and demonstrates a pathway for potential communication between the nervous and immune system.

Romano, T.A., S. H. Ridgway and S.N. Haber. 1995. The Basal Ganglia of the White Whale, Delphinapterus leucas: A Comparative Study. Society of Neuroscience Proceedings. 21 (1):155.

Investigates basal ganglia of the white whale in comparison with other species.

Rommel, S.A., D.A. Pabst, W.A. McLellan, T.M. Williams and W.A. Friedl. 1994. Temperature Regulation of the Testes of the Bottlenose Dolphin (Tursiops truncatus): Evidence from Colonic Temperatures. Jour. Comp. Physiol. B 164: 130-134.

A specially designed rectal probe measured temperatures simultaneously in several positions in the region of the colon. These support the hypothesis that cooled blood from peripheral sites (dorsal fin and flukes) is introduced into the deep abdominal cavity and functions to regulate the temperature of arterial blood flow to the dolphin testes. This has implications for the reproductive success of active males exposed to tropical or warm water conditions.

St. Aubin, D.J., S.H. Ridgway and R.S. Wells. 1991. Thyroid Hormone Metabolism in Small Odontocetes. Ninth Biennial Conf. on the Biology of Marine Mammals, Dec. 5-9, Chicago, IL, p. 66.

Aspects of thyroid hormone (YH) balance were examined in captive and free-ranging beluga whales, Delphinapterus leucas, and bottlenose dolphins, Tursiops truncatus.

St. Aubin, D.J., S.H. Ridgway, R.S. Wells, and H. Rhinehart. 1996. Dolphin Thyroid and Adrenal Hormones: Circulating Levels in Wild and Semidomesticated Tursiops truncatus, and Influence of Sex, Age, and Season. Marine Mammal Science. 12 (1):1-13.

Biological and environmental influences on circulating adrenal and thyroid hormones were investigated in 36 wild and 36 semidomesticated Atlantic bottlenose dolphins, Tursiops truncatus, matched by age, sex, and time of year when the samples were collected. Levels of both cortisol and aldosterone were low in semidomesticated dolphins conditioned to present voluntarily their tails for blood sampling, an approach that appears to yield specimens representative of resting values for these constituents.

Shaffer, S.A., T.M. Williams and D.P. Costa. 1995. Blood Plasma Lactate and Glucose of a Freely Diving Bottlenose Dolphin (Tursiops gilli). (Abs.) 11th Biennial Conf. on the Biology of Marine Mammals, Orlando, FL, Dec. 14-18, p. 103.

An open-ocean trained dolphin dove repeatedly to depths of 60 and 140 meters, returning to the surface for blood sampling after each dive series. Samples showed post-dive lactate increase and a slight glucose increase, but no correlation of either with dive duration. Results indicate lactate increase may have been caused by the swimming effort and/or inter-dive recovery time.

Shaffer, S.A., D.P. Costa, and T.M. Williams. 1996. Exercise Performance of White Whales (Delphinapterus leucas). (Abs.) The Physiologist. 39 (5): A62.

Swimming behavior, respiration rates and blood chemistry of two white whales were studied during and post exercise by transit swimming next to a boat. Respiration rates decreased significantly as locomotor speed increased, contrasting sharply to terrestrial mammals during exercise. Observed blood chemistry (marked increases in blood plasma lactate, slight glucose decrease) and respiration rate changes indicate high speed swimming at the surface is costly.

Shaffer, S.A. 1996. Assessment of Physiological and Behavioral Adjustments in Diving and Exercise of Two Cetacean Species, Delphinapterus leucas and Tursiops gilli. Thesis, University of California Santa Cruz, 92 pp.

Diving profiles with oxygen stores and predictions of aerobic dive limits in two free-diving white whales.

Shoemaker, P. A. and S. H. Ridgway. 1991. Cutaneous Ridges in Odontocetes. Marine Mammal Science 7(1):66-74.

The authors took surface impressions of dolphin skin to quantify the tiny cutaneous ridges that run circumferentially around the body from head to dorsal fin. They suggest that the ridges may have some function in the sense of touch and in the hydrodynamic characteristics of the animal.

Simpson, J. G., W. G. Gilmartin, and S. H. Ridgway. 1970. Blood Volume and Other Hematologic Values in Young Elephant Seals (Mirounga angustirostris). Am. Jour. Vet. Res. 31(8):1449-1452.

A mean blood volume of 216 ml/kg and a mean packed cell volume of 64 percent were found. The elephant seal, with the mean blood volume representing 20 percent or more of body weight, has the highest reported blood volume of any mammal.

Simpson, J. G., and M. B. Gardner. 1972. Comparative Microscopic Anatomy of Selected Marine Mammals. In: Mammals of the Sea--Biology and Medicine, S. H. Ridgway (ed.). Chas. C. Thomas Publ., Springfield, IL, pp. 298-418.

Profusely illustrated paper on the histology of organs and systems in certain cetaceans and pinnipeds, with emphasis on pathology.

Stromberg, M. W. 1985. Fat Distribution in the Skin of Bottlenosed Dolphins (Tursiops truncatus and Tursiops gilli). Jour. Morphology 186 (3): 315-326.

Fat was rather evenly distributed in all strata of the epidermis. Unique extracellular fat droplets were observed among the collagen bundles of the dermis and unusual lipid particles were in some vessels of the dermal papillae. A unique extracellular transport of dermal lipids to the epidermis is postulated. Possible functions of epidermal lipids are discussed.

Stromberg, M. W. 1989. Dermal-epidermal Relationships in the Skin of the Bottlenosed Dolphin (Tursiops truncatus). Jour. Vet. Med., Series C: Anat. Histol. Embryol. 18:1-13.

Dolphin skin was studied by a variety of methods. The arrangement of dermal and corresponding epidermal structure is described. Distinct epidermal pegs were not observed. Results are compared with information in recent literature. Apparent conflicts are discussed. The structure and scale of epidermal ridges are detailed.

Sweeney, J. C. 1974. Radiographic Atlas of the California Sea Lion. NUC TP 387, 16 pp.

A radiographic reference atlas with an evaluation of techniques for all of the standard positions. Includes photographs and drawings of the normal radiographic anatomy.

Tarpley, R. J., and S. H. Ridgway. 1991. Orbital Gland Structure and Secretions in the Atlantic Bottlenosed Dolphin (Tursiops truncatus). Jour. Morphology 207:1-12.

The anatomy of the orbital gland that surrounds the dolphin’s eye was elucidated in numerous drawings, photographs, and photomicrographs. The gland secretes the visco-elastic tear secretion of dolphins and some of the properties of this secretion are discussed.

Tarpley, R.J. and S.H. Ridgway. 1991. Correlations of Corpus Callosum Size in Odontocete Cetaceans. (Abs.) Society for Neuroscience Abstracts. 17: 257.13.

The midsagittal surface area of the corpus callosum was determined by computer-assisted morphometer in four odontocete cetacean families (Delphinidae, Monodontidae, Physeteridae and Ziphiidae) and correlated with brain weight and cerebral cortical surface area.

Tarpley, R.J., J.B. Gelderd, S. Bauserman and S.H. Ridgway. 1994. Dolphin Peripheral Visual Pathway in Chronic Unilateral Ocular Atrophy: Complete Decussation Apparent. Jour. Morphology. 222:91-102.

Provides anatomical documentation and both light and electron microscopy employing special staining, demonstrating the fibers from each dolphin eye are directed to the opposite cerebral hemisphere.

Tarpley, R.J. and S.H. Ridgway. 1994. Corpus Callosum Size in Delphinid Cetaceans. Brain, Behavior and Evolution. 44:156-165.

Measurements of corpus callosum size in a group of animals from different cetacean species demonstrate that the corpus callosum, the large bundle of nerve fibers that connect the two cerebral hemispheres, is relatively small compared to total brain size.

Wever, E. G., J. G. McCormick, J. Palin, and S. H. Ridgway. 1971. The Cochlea of the Dolphin (Tursiops truncatus): Hair Cells and Ganglion Cells. Proc. Nat. Acad. Sci. USA 68 (12):2908-2912.

The large number of hair cells found suggests a high order of auditory proficiency, and the large ratio of ganglion cells to hair cells suggests an unusual ability to utilize auditory information.

Wever, E. G., J. G. McCormick, J. Palin, and S. H. Ridgway. 1971. The Cochlea of the dolphin (Tursiops truncatus): General Morphology. Proc. Nat. Acad. Sci. USA 68 (10): 2381-2385.

Describes the microscopic structure of the cochlea and discusses features believed to represent adaptations for the reception of high-frequency sounds.

Wever, E. G., J. C. McCormick, J. Palin, and S. H. Ridgway. 1971. Cochlea of the Dolphin (Tursiops truncatus): The Basilar Membrane. Proc. Nat. Acad. Sci. USA 68 (11): 2708-2711.

Describes the microscopic structure of the basilar membrane and notes features suggesting unusual capabilities of pitch discrimination at very high frequencies.

Williams, T.M., W.A. Friedl and J.E. Haun. 1991. Swimming by Bottlenose Dolphins (Tursiops truncatus): Odontocete Olympians or Sedentary Cetaceans? (Abs.) Ninth Biennial Conf. on the Biology of Marine Mammals, Chicago, IL, Dec. 5-9, p. 74.

Reports on assessment of aerobic and anaerobic energetic costs for swimming dolphins, measured through heart rate, respiratory rate and post-exercise blood lactate concentration. Concludes dolphins are capable of maintaining high work loads during static exercise. Routine swimming is energetically inexpensive.

Williams, T.M., J.E. Haun, W.A. Friedl, R.W. Hall and L.W. Bivens. 1991. Assessing the Thermal Limits of Bottlenose Dolphins: A Cooperative Study by Trainers, Scientists, and Animals. Annual IMATA Conf., Vallejo, CA, Nov. 4-8, 1991.

Discusses a study of the thermoregulatory physiology of adult bottlenose dolphins (Tursiops truncatus) to determine the range of thermally neutral water temperatures for these cetaceans.

Williams, T.M., W.A. Friedl and J.E. Haun. 1992. Assessing the Physiological limits of Exercise Performance in Bottlenose Dolphins. (Abs.) The Physiologist. 35 (4): 224.

Examines the relationship among aerobic and anaerobic costs of exercise, oxygen stores and level of effort in swimming and diving bottlenose dolphins (Tursiops truncatus). The dolphin's dynamic metabolic scope and level of maximal oxygen consumption fell short of those reported for elite terrestrial athletes such as horses and dogs. Oxygen stores were an important avenue of metabolic support during diving and swimming at routine speeds.

Williams, T.M., W.A. Friedl and J.E. Haun. 1993. The Physiology of Bottlenose Dol phins (Tursiops truncatus): Heart Rate, Metabolic Rate and Plasma Lactate Concentration During Exercise. Jour. Exp. Biol. 179: 31-46.

Study examained physiological responses and locomotor energetics of two exercising adult Tursiops, measuring three indicators (heart rate, etc.) for the animals while pushing against a load cell and swimming next to a boat. Concludes the energetic cost of swimming for Tursiops is low in comparison to that of other aquatic and semi-aquatic mammals.

Williams, T.M., R.W. Davis, M.A. Castellini, T.R. Loughlin, D.G. Calkins and J. Sease. 1993. The Relationship Between Body Condition and Thermoregulatory Costs in Steller Sea Lion Pups. (Abs.) Tenth Biennial Conf. on the Biology of Marine Mammals, Galveston, TX, Nov. 11-15, p. 17.

Reports on examination of the quality and quantity of blubber in Steller sea lion pups and its effect on heat loss and thermal costs. Differences were determined in blubber thickness (coincident with body mass) and insulation quality and in thermal energetic costs between pups from rookeries on different islands.

Williams, T.M., S.F. Shippee and M.J. Rothe. 1996. Strategies for Reducing Foraging Costs in Dolphins. In: Aquatic Predators, S. Greenstreet and M.L. Tasker (eds.) Blackwell Science Ltd., London, pp. 4--9.

Discusses a study of energetic costs associated with, and restricting time for, foraging. This effort addresses energy costs of locomotion, thermoregulation and digestion for bottlenose dolphins (Tursiops truncatus) and concludes their behaviors to reduce these costs benefit foraging animals by conserving limited oxygen reserves during a dive.

Woods, D. L., S. H. Ridgway, and T. H. Bullock. 1986. Middle- and Long-Latency Auditory Event-Related Potentials in Dolphins. In: Dolphin Cognition and Behavior, R. J. Schusterman, J. A. Thomas, and F. G. Wood (eds.). Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 61-77.

In recordings of event-related potentials in response to a variety of auditory stimuli, certain responses suggested a more precise representation of auditory stimuli in short-term memory in dolphins than in humans. Infrequent "deviant" stimuli produced a component similar in some respects to the "decision-related" P300 wave in humans.