Subject: Regurgitation in wild dolphins
Dear list members,
Diving and swimming around the daily (very restricted) home-range of the
solitary sociable Indian Ocean bottlenose dolphin (T. aduncus) in Sinai, we
regularly find regurgitated fish bones (mainly whole skulls and skull
elements) in a very good state on the sandy bottom. On few occasions,
we have obsereved her in the act of regurgitation, in which very clean
bones (devoid of soft tissues) are ejected amongst a powdery-clouded
(ground bones?)
water jet.
We would like to know if this is the normal pattern in dolphins, vomiting
out large bony elements
which are not mechanically disintegrated in the fore stomach, or is this a
specific/individual behavior? We found several references discribing or
alluding to
regurgitation of food debris and foreign objects by captive bottlenose
dolphins, ie:
Caldwell and Caldwell (1987): Foregion objects ingestion by Atlantic
Bottlenose Dolphins;
Accident or Design. Abstrac: Seventh bien. conf. Biology of Marine Mammals.
Dec. 1987, Miami.
Harrison, RJ et al. (1970): The oesophagus and stomach of dolphins (Tursiops,
Delphinus and Stenella). J. Zool. 160:377-390.
But nothing in wild animals.
We wonder if any of you had occasion to observe similar behavior in the
wild, or can direct us
to published information that we have missed. A summary of your responses
will be posted to
the list.
Many thanks,
Dan Kerem, Ph.D.
President,
IMMRAC (Israeli Marine Mammal Research and Assistance Center)
The Recanati Institute for Maritime Studies
The University of Haifa
Mount Carmel, Haifa 31905
Israel
e-mail: dankerem@research.haifa.ac.il
Tel: + 972-4-8249449 Fax: + 972-4-8240493
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