Seasonal changes of blood composition in captive bottlenose dolphins

To determine how blood values in bottlenose dolphins changed during the year, 504 blood samples were taken from 9 dolphins from 1991 to 1999 and clinical blood examinations were undertaken monthly including 3 hematological and 19 serum chemistry tests. In creatinine, significant seasonal changes were found among three groups of adult males, adult females and juveniles, and the average values in summer were 15-38% higher than those in winter. In two out of three groups the average total cholesterol value were highest in winter, and the lowest of all groups were in summer. In two other groups the peaks of average FFA value were recorded in summer, and the lows were in winter.     

Sonographic evaluation of thyroid morphology during the normal estrous cycle in the Indo-Pacific bottlenose dolphin (Tursiops aduncus)

Physiologic changes occurring in the thyroid in response to the estrous cycle have been noted in companion animals. However, in bottlenose dolphins, the influence of different reproductive states on thyroid morphology remains unclear. Sonography was used to evaluate the variations of thyroid morphology for nine consecutive estrous cycles of four sexually mature, female Indo-Pacific bottlenose dolphins (Tursiops aduncus). The estrous cycle was divided into two phases for evaluation: the follicular and luteal phases. To compare changes associated with sex, thyroid volumes were measured in the different phases during the estrous cycle of female dolphins and were compared to the ultrasound examinations of the four male dolphins measured over a 2-mo period. In males, there was no significant difference in thyroid volume during the study period (P > 0.05). The thyroid volume measured in combining all estrous cycle phases of the female dolphins was significantly larger than that measured in the male dolphins (P < 0.05). A difference in thyroid volume during the estrous cycle was observed, with the thyroid volume during the follicular phase significantly smaller (P < 0.05) than that of the luteal phase, and is possibly related to the influence of female sex steroids. Thyroid volume variability during estrus should, therefore, be taken into account when examining the thyroid gland of female dolphins.     

Haematological findings in captive dolphins and whales

Objective To examine haematological features in five species of healthy, captive marine mammals.
Animals Twenty bottlenose dolphins ( Tursips truncatus ), seven Pacific white-sided dolphins ( Lagenorhynchus obliquidens ), five Risso dolphins ( Grampus griseus ) and five false killer whales ( Pseudorca crassidens ).
Results and conclusion The red blood cell count was 4.21 × 10¹²/L in bottlenose dolphins, 5.32 × 10¹²/L in Pacific white-sided dolphins, 4.35 × 10¹²/L in Risso dolphins and 4.43 × 10¹²/L in false killer whales. The haemoglobin concentration was 1.51 g/L and packed cell volume 44.7% in bottlenose dolphins; the corresponding values were 1.71 g/L and 48.9% in Pacific white-sided dolphins, 1.72 g/L and 49.4% in Risso dolphins, and 1.52 g/L and 47.8% in false killer whales. The white blood cell count was 7.097 × 10⁹/L in bottlenose dolphins, 5.928 × 10⁹/L in Pacific white-sided dolphins, 5.001 × 10⁹/L in Risso dolphins and 7.921 × 10⁹/L in false killer whales. There were no significant differences in these values among bottlenose dolphins and Pacific white-sided dolphins. The proportion of eosinophils in the differential leukocyte count ranged from 10.3% to 11.5% in bottlenose dolphins, Pacific white-sided dolphins and false killer whales, but was only 0.4% in Risso dolphins. The eosinophilic granules were larger in Risso dolphins and false killer whales than in bottlenose and Pacific white-sided dolphins.     

Development and validation of monoclonal and polyclonal antibodies for the detection of immunoglobulin G of bottlenose dolphins (Tursiops truncatus).

Antibodies directed against species-specific immunoglobulin G (IgG) have a broad range of applications in serologic and immunologic research and in the development of clinical assays. Validated anti-IgG antibodies for marine mammal species are in short supply. The objective of this study was to produce and validate antibodies with specificity for IgG of the common bottlenose dolphin (Tursiops truncatus). Bottlenose dolphin IgG was purified using protein G. Two mouse monoclonal antibodies and a rabbit polyclonal antibody were developed from mice and rabbits immunized with bottlenose dolphin IgG. The specificity of the monoclonal antibodies and the polyclonal antibody for bottlenose dolphin IgG was first verified by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). For further validation, both monoclonal antibodies and the polyclonal antibody were incorporated in an indirect ELISA for the detection of the immune response of bottlenose dolphins to a vaccine antigen. Three bottlenose dolphins were immunized with a commercial Erysipelothrix rhusiopathiae vaccine, and serial blood samples were collected from all dolphins for measurement of levels of circulating antibodies. Seroconversion was observed in all 3 dolphins by use of both monoclonal antibodies and the polyclonal antibody. Circulating antibodies were detectable as early as 6 days after immunization in 1 dolphin. Peak antibody levels were detected 14 days after the immunization. The ability to detect seroconversion in all 3 immunized bottlenose dolphins firmly establishes the specificity of the monoclonal antibodies and the polyclonal antibody for IgG of the common bottlenose dolphin.     

Thoracic auscultation in captive bottlenose dolphins (Tursiops truncatus), California sea lions (Zalophus californianus), and South African fur seals (Arctocephalus pusillus) with an electronic stethoscope

Thoracic auscultation is an important diagnostic method used in cases of suspected pulmonary disease in many species, as respiratory sounds contain significant information on the physiology and pathology of the lungs and upper airways. Respiratory diseases are frequent in marine mammals and are often listed as one of their main causes of death. The aim of this study was to investigate and report baseline parameters for the electronic-mediated thoracic auscultation of one cetacean species and two pinniped species in captivity. Respiratory sounds from 20 captive bottlenose dolphins (Tursiops truncatus), 6 California sea lions (Zalophus californianus), and 5 South African fur seals (Arctocephalus pusillus) were recorded with an electronic stethoscope. The sounds were analyzed for duration of the respiratory cycle, adventitious sounds, and peak frequencies of recorded sounds during expiration and inspiration as well as for sound intensity as reflected by waveform amplitude during the respiratory cycle. In respiratory cycles of the bottlenose dolphins' expiring "on command," the duration of the expiration was significantly shorter than the duration of the inspiration. In the examined pinnipeds of this study, there was no clear pattern concerning the duration of one breathing phase: Adventitious sounds were detected most often in bottlenose dolphins that were expiring on command and could be compared with "forced expiratory wheezes" in humans. This is the first report of forced expiratory wheezes in bottlenose dolphins; they can easily be misinterpreted as pathologic respiratory sounds. The peak frequencies of the respiratory sounds reached over 2,000 Hz in bottlenose dolphins and over 1,000 Hz in California sea lions and South African fur seals, but the variation of the frequency spectra was very high in all animals. To the authors' knowledge, this is the first systematic analysis of respiratory sounds of bottlenose dolphins and two species of pinnipeds.     

Malignant seminoma with metastasis, Sertoli cell tumor, and pheochromocytoma in a spotted dolphin (Stenella frontalis) and malignant seminoma with metastasis in a bottlenose dolphin (Tursiops truncatus)

Seminoma with metastasis was diagnosed in a spotted dolphin (Stenella frontalis) and an Atlantic bottlenose dolphin (Tursiops truncatus). Sertoli cell tumor and pheochromocytoma were also diagnosed in the spotted dolphin. The spotted and bottlenose dolphins were adult males that stranded and died on the coasts of northwest Florida and southeast North Carolina, respectively. Neoplasia is infrequently reported in cetaceans. This is the first report of seminoma, Sertoli cell tumor, and pheochromocytoma in a dolphin, the first report of three distinct neoplasms in a dolphin, and one of the few reports of malignant neoplasia in dolphins.     

The seasonal fluctuation of plasma amino acids in aquarium-maintained bottlenose dolphins (Tursiops truncatus)

Although there has been extensive research on plasma amino acid profiles of mammals, there is currently a lack of information on seasonal differences in the concentrations of plasma amino acids specifically in cetaceans. The present study examined the response of the plasma amino acids to seasonal changes in the culture environment after controlling for the effect of sex and age. Significant seasonal changes in plasma carnosine (P=0.012), cystine (P=0.0014), isoleucine (P=0.0042), methionine (P=0.002), ornithine (P=0.0096), and taurine (P=0.032) were observed. These amino acids were mainly related to capacity for exercise, ammonia detoxification, thermoregulation, and osmoregulation. We proposed that optimizing plasma amino acids levels by supplementation of amino acids should be of considerable benefit for aquarium-maintained bottlenose dolphins. This study constitutes a first step towards improving our understanding of the metabolism of aquarium-maintained bottlenose dolphins. We also revealed that the ratio of tryptophan to large neutral amino acids significantly declined (P=0.0076), suggesting reduction in serotonin synthesis in winter and autumn. Although further studies are needed, this finding implied that bottlenose dolphins could produce behavioral changes seasonally by the alteration of serotonin activity. To better understand the metabolic machinery for amino acids that facilitate the adaptation of marine mammals to their environments, it is essential to continue monitoring of and further investigations into relationships between plasma amino acids and specific environmental factors.     

Bartonella species detection in captive, stranded and free-ranging cetaceans

We present prevalence of Bartonella spp. for multiple cohorts of wild and captive cetaceans. One hundred and six cetaceans including 86 bottlenose dolphins (71 free-ranging, 14 captive in a facility with a dolphin experiencing debility of unknown origin, 1 stranded), 11 striped dolphins, 4 harbor porpoises, 3 Risso's dolphins, 1 dwarf sperm whale and 1 pygmy sperm whale (all stranded) were sampled. Whole blood (n = 95 live animals) and tissues (n = 15 freshly dead animals) were screened by PCR (n = 106 animals), PCR of enrichment cultures (n = 50 animals), and subcultures (n = 50 animals). Bartonella spp. were detected from 17 cetaceans, including 12 by direct extraction PCR of blood or tissues, 6 by PCR of enrichment cultures, and 4 by subculture isolation. Bartonella spp. were more commonly detected from the captive (6/14, 43%) than from free-ranging (2/71, 2.8%) bottlenose dolphins, and were commonly detected from the stranded animals (9/21, 43%; 3/11 striped dolphins, 3/4 harbor porpoises, 2/3 Risso's dolphins, 1/1 pygmy sperm whale, 0/1 dwarf sperm whale, 0/1 bottlenose dolphin). Sequencing identified a Bartonella spp. most similar to B. henselae San Antonio 2 in eight cases (4 bottlenose dolphins, 2 striped dolphins, 2 harbor porpoises), B. henselae Houston 1 in three cases (2 Risso's dolphins, 1 harbor porpoise), and untyped in six cases (4 bottlenose dolphins, 1 striped dolphin, 1 pygmy sperm whale). Although disease causation has not been established, Bartonella species were detected more commonly from cetaceans that were overtly debilitated or were cohabiting in captivity with a debilitated animal than from free-ranging animals. The detection of Bartonella spp. from cetaceans may be of pathophysiological concern.     

Season,sex and age variation in the haematology and body condition of geometric tortoises Psammobates geometricus

Body condition and haematological indices provide powerful information when assessing wildlife health. Reference intervals for these indices can facilitate wildlife management, and would benefit initiatives to save the Critically Endangered geometric tortoise (Psammobates geometricus). We collected data from 126 geometric tortoises to establish baseline values reflecting variation over four seasons (spring 2000 to winter 2001) and among three groups (female, male and juvenile). We measured body condition index (BCI; mass to shell volume), blood urea nitrogen (BUN), plasma chloride, packed cell volume (PCV), haemoglobin concentration (Hb) and red blood cell count (RBC), and used PCV, Hb and RBC to calculate erythrocyte indices. BCI correlated poorly with haematological measures but had a strong inverse relationship with BUN. BCI did not vary among groups, but all groups had low condition indices in autumn, the end of the dry season. High BUN and chloride values in autumn indicate dehydration, particularly in males. Males had the highest PCV, Hb and RBC values, especially during summer and autumn when they moved long distances, likely pursuing mates. Female and juvenile indices were similar, except that female Hb was higher than juvenile Hb, possibly to meet female energy needs associated with their large size and reproductive metabolism. Low Hb levels in winter coincided with low temperatures and reduced movements. Our results illustrate how intrinsic and extrinsic factors influence the physiology of geometric tortoises and provide reference intervals to monitor their health.     

Behavior and salivary cortisol of captive dolphins (Tursiops truncatus) kept in open and closed facilities

Few studies have been carried out on the welfare of captive bottlenose dolphins (Tursiops truncatus). Of these, most include information on animals kept in closed facilities or pools. The aim of this study was to assess the welfare of captive bottlenose dolphins in open and closed facilities by measuring states of individual behavior and salivary cortisol concentrations. A total of 23 bottlenose dolphins were studied in 4 different dolphinaria. Dolphinaria A and B have closed facilities, whereas dolphinaria C and D have open facilities. A total of 152 hours of behavioral observations were analyzed using a combination of behavior and scan sampling to obtain information on individual time budgets. Salivary cortisol concentrations were measured using radioimmunoassay in 96 and 180 saliva samples of dolphins kept in closed and open facilities, respectively. In general, the results found that dolphins kept in open facilities spent less time floating (P < 0.05) and swimming in circular patterns than linear ones (P < 0.05) compared with dolphins in closed facilities. Dolphins kept in open facilities also had lower salivary cortisol concentrations than dolphins kept in closed facilities (P < 0.05). For this reason, we suggest that further research should include other welfare indicators such as reproductive function and health measurements to know more about the relationships between the design of pools and dolphin welfare.     

Lobomycosis in Atlantic bottlenose dolphins from the Indian River Lagoon, Florida

OBJECTIVE: To determine the prevalence of lobomycosis, a mycotic infection of dolphins and humans caused by a yeastlike organism (Lacazia loboi), among dolphins in the Indian River Lagoon in Florida. DESIGN: Cross-sectional study. ANIMALS: 146 Atlantic bottlenose dolphins. PROCEDURE: Comprehensive health assessments of bottlenose dolphins in the Indian River Lagoon of Florida (n = 75) and in estuarine waters near Charleston, SC (71), were conducted during 2003 and 2004. Bottlenose dolphins were captured, examined, and released. Skin lesions were photographed and then biopsied. Tissue sections were stained with H&E and Gomori methenamine silver stains for identification of L. loboi. RESULTS: 9 of 30 (30%) dolphins captured in the southern portion of the Indian River Lagoon had lobomycosis, whereas none of the 45 dolphins captured in the northern portion of the lagoon or of the 71 dolphins captured near Charleston, SC, did. Affected dolphins had low serum alkaline phosphatase activities and high acute-phase protein concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lobomycosis may be occurring in epidemic proportions among dolphins in the Indian River Lagoon. Localization of the disease to the southern portion of the lagoon, an area characterized by freshwater intrusion and lower salinity, suggests that exposure to environmental stressors may be contributing to the high prevalence of the disease, but specific factors are unknown. Because only dolphins and humans are naturally susceptible to infection, dolphins may represent a sentinel species for an emerging infectious disease.     

Relationship between plasma iron concentration and gastric pH in captive adult bottlenose dolphins (Tursiops truncatus)

OBJECTIVE: To determine the correlation between plasma iron concentrations and gastric pH in a population of captive Atlantic bottlenose dolphins (Tursiops truncatus). ANIMALS: 6 adult female dolphins that ranged from 16 to 30 years of age. PROCEDURES: Blood and gastric samples were collected from each dolphin to allow measurement of plasma iron concentrations and gastric pH, respectively. Samples were collected each month for 12 months. RESULTS: Within each dolphin, plasma iron concentrations and gastric pH did not differ significantly over time. There was a strong negative correlation (r = -0.85) between plasma iron concentration and gastric pH, which suggested that dolphins with a lower gastric pH had a higher plasma iron concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of results reported here suggested that gastric pH may play an important role in iron absorption in dolphins.     

Effects of duration of capture and sample handling on critical care blood analytes in free-ranging bottlenose dolphins

OBJECTIVE: To determine effects of duration of capture and sample-handling procedures on blood analytes in free-ranging bottlenose dolphins. DESIGN: Cross-sectional study. ANIMALS: 154 free-ranging bottlenose dolphins of various ages and both sexes. PROCEDURES: Blood samples were drawn from each dolphin within 10 minutes of capture and before release and analyzed by use of a portable analyzer with a single-use 8-analyte disposable cartridge. Analyte values were compared according to duration between sample acquisition and analysis (time to run [TTR]) and duration between net encirclement and sample acquisition (time to bleed [TTB]). RESULTS: Neither TTB nor TTR significantly affected sodium or chloride concentration. Potassium concentration was not significantly affected by TTR, whereas the effect of TTB was significant. Glucose, total CO(2), HCO(3), Hct, and base excess of extracellular fluid values were significantly affected by TTR. Increased TTB resulted in significantly increased total CO(2), HCO(3), and base excess when TTR was kept within 10 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: The effect of TTB on certain acid-base and electrolyte values was readily measured in free-ranging bottlenose dolphins, and such values may provide a reference range for those variables.     

Hyperlipemia of captive bottlenose dolphins during pregnancy

In this study values for total cholesterol and triglycerides were measured in 110 blood samples taken from 360 days pre-partum to 90 days post-partum in ten parturitions of six bottlenose dolphins, and in 75 blood samples when the dolphins were not pregnant as a control group. The average total cholesterol values in the second, third and fourth stages and in the puerperium were significantly higher than the average value of the control group by 11.0%, 30.2%, 19.3% and 13.4% respectively. The average triglycerides values for the third and fourth stages and in the puerperium were also significantly higher than those in the control group by 59.7%, 84.3%, and 42.1% respectively.     

Infection with Brucella ceti and high levels of polychlorinated biphenyls in bottlenose dolphins (Tursiops truncatus) stranded in south-west England

Eight bottlenose dolphins (Tursiops truncatus) that stranded in Cornwall, south-west England, between June 2004 and December 2007 were examined using standardised postmortem examination and bacteriological methods. Evidence of Brucella species infection was found in four of these dolphins on culture. In addition, of the eight dolphins, four were positive and two were weakly positive for antibodies to Brucella species on serological analyses of pericardial and other fluids using a competitive ELISA and two indirect ELISAs. High or very high levels of the sum of 25 individual chlorobiphenyl congeners (∑25CBs) were also determined in blubber samples from two of the dolphins (45.5 and 446.6 mg/kg lipid weight).     

Dermatitis with invasive ciliated protozoa in dolphins that died during the 1987-1988 Atlantic Bottlenose Dolphin morbilliviral epizootic

Dermatitis with intradermal cilated protozoa was identified in 18 of 95 (19%) Atlantic Bottlenose Dolphins (Tursiops truncatus) that died during the 1987-1988 Atlantic-dolphin morbillivirus epizootic. The lesions were characterized by focally extensive suppurative and histiocytic dermatitis and cellulitis with ulceration and variable numbers of dermal and hypodermal ciliates. Vasculitis, thrombosis, and/or intravascular ciliates were rarely present. In one dolphin, there was an associated lymphadenitis with ciliates, and in another, bronchopneumonia with rare intrabronchiolar ciliates. Ten of the dolphins were female, and eight were male. The animals ranged in length from 148 to 260 cm. Eleven were from Virginia, four were from New Jersey, and three were from Florida. In 13 dolphins, results of immunohistochemical and/or polymerase chain reaction (PCR) tests were positive for morbillivirus infection. Results of immunohistochemical tests were negative in four dolphins that were not also tested with PCR. Results were also negative in one dolphin tested using both methods. Nine dolphins had concomitant bacterial, fungal, and/or other protozoal infections. Fourteen other dolphins with ciliate-associated dermatitis were identified from 414 Atlantic bottlenose dolphin cases (3%) archived at the Armed Forces Institute of Pathology. The incidence of dermatitis with invasive ciliates is much greater in dolphins that died during the 1987-1988 epizootic.     

Simultaneous measurement of phagocytosis and respiratory burst of leukocytes in whole blood from bottlenose dolphins (Tursiops truncatus) utilizing flow cytometry

Phagocytic and respiratory burst activity was simultaneously measured by flow cytometry in polymorphonuclear leukocytes (PMN) and monocytes in whole blood from bottlenose dolphins (Tursiops truncatus). Blood was collected from 16 adult dolphins, 12 males (6-34 years of age) and 4 females (11-30 years) and subsequently incubated with a bacteria-to-leukocyte ratio of 25:1 and 10 μl of 500 μM 2',7'-dichlorofluorescein diacetate for 70 min at 37°C. PMN (44.5 ± 3.2%) and monocytes (33.5 ± 3.0%) were positive for propidium iodide-labeled Staphylococcus aureus, indicating phagocytosis. Respiratory burst activity after 70 min as measured by the mean fluorescence intensity (MFI) was 68.0 ± 14.4 in PMN and 47.0 ± 10.3 in monocytes. There were no significant differences in MFI or percentage of phagocytizing PMN (p > 0.094) or monocytes (p > 0.275) after storage at 4°C for 24h when compared to activity measured in fresh blood. Nor was there an effect of storage on respiratory burst activity (MFI or percentage) in PMN (p > 0.420) or monocytes (p > 0.301). This assay may be particularly useful to assess the ability of dolphins to effectively combat bacterial pathogen challenges with minimal amounts of blood.     

不同季节肉用种公牛精液品质与生理常值、血清及精清生化指标相关关系研究

以利木赞和夏洛来种公牛为试验牛，研究不同季节对其精液品质、冻精产量、生理常值、血清及精清生化指标的影响。结果表明：（1）与其它季节相比，夏季肉用种公牛的原精活力、冻精活力、活精于百分数、顶体完整率均显著降低，而精于畸形率显著升高（P〈0．05）。精子密度以秋季最低。（2）冻精产量夏季处于最低水平，平均每月仅为7388支。（3）夏季肉用种公牛的血清LH、睾酮、T3、皮质醇的含量分别为48．12、4．15、1．11、4．89ng／L，显著低于春、秋、冬季（P〈0．01）。（4）夏季肉用种公牛血清钠、钾、钙、镁均处于最低水平，显著低于其它季节（P〈0．01）。（5）夏季肉用种公牛精清睾酮水平明显下降，显著低于春季、秋季和冬季。（6）精清钠、钾、钙夏季含量最低，分别为83．12mmol／L、18，77mmol／L和4．63mmol／L；精清镁含量由春季至秋季呈显著下降趋势；精清磷含量夏季最高，为4．65mmol／L，显著高于春季、秋季和冬季。（7）肉用种公牛精清ALP夏季含量为1784．3U／L，显著高于春、秋两季，但低于冬季。（8）精清睾酮与精液品质各指标存在显著相关；血清生化指标与精清生化指标存在显著相关；直肠温度、呼吸频率与精液品质及血清生化指标存在显著相关性，与精清生化指标相关性不大。     

Cold stress induces an adrenocortical response in bottlenose dolphins (Tursiops truncatus)

Two adult bottlenose dolphins (Tursiops truncatus) were individually housed in aboveground pools over a 10-day period and exposed to decreasing water temperatures to determine whether cold stress activated the hypothalamic-pituitary-adrenal axis. To serve as controls, two additional adult dolphins were similarly housed for the same duration but at ambient water temperatures (16.8-19.6 degrees C). Across all subjects, water temperatures ranged from 4.2 to 19.6 degrees C. Voluntary blood draws were made from each dolphin every 2-3 days, and serum was analyzed via radioimmunoassay for cortisol and aldosterone. Dolphins exposed to cold water showed an increase in serum cortisol and aldosterone as temperature declined; at the coldest water exposure, cortisol was more than three times and aldosterone more than two times the levels measured at ambient temperature. Elevations occurred before the water temperature declined below the individual animal's lower critical temperature, the point at which the metabolic rate increases to compensate for the loss of body heat. Variations in corticosteroids were unrelated to the 10-day isolation period, suggesting that the response was related to the cold stress and not impacted by the isolation. Elevations in cortisol and aldosterone were lower than those observed in force captured and stranded dolphins. Although potentially related to the general adaptive stress response, elevations in cortisol and aldosterone may have other adaptive functions related to mitigating impacts resulting from cold environmental temperatures.     

Echocardiographic evaluation of the bottlenose dolphin (Tursiops truncatus).

Safe and effective echocardiography would represent a valuable tool for marine mammal veterinarians and physiologists evaluating the dolphin heart. Unfortunately, conventional ultrasound technology (transthoracic echocardiography) has been limited by logistic, anatomic, and behavioral challenges. Five mature male Atlantic bottlenose dolphins (Tursiops truncatus) were trained for echocardiographic imaging (four for both transthoracic and transesophageal imaging, and one for only transthoracic imaging). It was noted that transesophageal image quality transiently improved when the dolphins spontaneously exhaled. Subsequently, dolphins were conditioned to hold their breath following forced exhalation, and imaging proceeded during such behavioral breath holds. Over 25 transthoracic and 100 transesophageal echocardiographic studies were performed, including both two-dimensional imaging and color flow mapping. Transthoracic imaging yielded poor-quality images of only small portions of the heart. In contrast, transesophageal imaging, which improved dramatically with behavioral breath holding following exhalation, yielded consistently high-quality images of the entire heart (mitral, tricuspid, aortic, and pulmonary valves, atrial and ventricular septa, left and right atria, left and right ventricles, and ascending aorta and main pulmonary artery). Color flow mapping demonstrated mild tricuspid regurgitation in all dolphins, and mild aortic regurgitation in one dolphin found to have a pedunculated mass arising from the sinutubular junction just above the aortic valve. There were no complications in nonsedated dolphins. The heart of the bottlenose dolphin can be safely, effectively, and reproducibly evaluated with the use of transesophageal echocardiography in conjunction with behavioral breath holding following forced exhalation. This approach, and the normative echocardiographic data generated from this work, lays the foundation for future echocardiographic studies of cetaceans.