Dolphin Calves Research Articles

The lungworm, Halocercus spp. (Nematoda: Pseudaliidae) in cetaceans from California.

Three cetaceans from Monterey Bay, California (USA), were infected with lung nematodes. A beaked whale calf, Mesoplodon sp. was infected with adult Halocercus sp. This represents a new host record for this nematode. The lungs of a northern right whale dolphin calf, Lissodelphis borealis, contained an unidentified nematode similar in size to Halocercus sp. The presence of Phyllobothrium delphini-type cestode larvae in its blubber is evidence that the calf was feeding on invertebrates. A pregnant harbor porpoise, Phocoena phocoena was infected with the lung nematode H. invaginatus, but the fetus was uninfected. We found no direct evidence of a transplacental mode of transmission for Halocercus sp.

Commerson's dolphin (Cephalorhynchus commersonii): A discussion of the first live birth within a marine zoological park

AbstractSix adult Commerson's dolphins (Cephalorhynchus commersonii) have been housed at Sea World, San Diego, since 1983. Details of their husbandry at Sea World are briefly presented. Pregnancy was determined in one of the females by means of radioimmunoassay, following observations of copulation. Food consumption of the pregnant female decreased beginning 5 days prior to parturition and ceased entirely 6 hours prior to delivery. A single male calf, 55–65 cm in length and weighing 4.5–5.5 kg, was delivered after 35 minutes of labor. Details of the delivery, calf's appearance, suckling behavior, and early respiratory pattern are presented. Similarities between the birth of the Commerson's dolphin calf and previous births of bottlenosed dolphin (Tursiops truncatus) calves are discussed. The successful propagation of new species, such as Commerson's dolphins, permits documentation of the event with greater detail and accuracy than is possible in the wild. Details of growth and reproduction thus gained may provide information applicable to the natural history and proper management of the species in question.

Apparent echolocation by a sixty-day-old bottlenosed dolphin, Tursiops truncatus

Little is known about the ontogeny of echolocation in dolphins. A bottlenosed dolphin calf born at our facility in San Diego Bay was observed continuously for two hours each day and randomly at other times. Squeals were heard about ten seconds after birth and whistlelike calls soon thereafter but we did not notice head scanning movements concurrent with high-frequency pulses until the dolphin's sixtieth day of life. On this day we noticed that the calf would examine items such as a human foot inserted in the water by approaching, head scanning, and pulsing. A hydrophone placed in the water elicited the same behavior. Seven pulse trains were recorded at distances of 1–3 m. Peak frequencies ranged from 33 to 120 kHz with 3-dB bandwidths of 28–81 kHz.