|The Mammals of Texas -
Gervais' Beaked Whale
Cetacea : Family Ziphiidae : Mesoplodon
Description. A rather small whale with a
prominent beak and only one large tooth in each lower
jaw, placed about 15 cm back from the tip and beside the
posterior end of the symphysis of the lower jaws. In
males this tooth is large, protrudes from the closed
mouth, and fits into a groove in the skin of the upper
lip; in females the tooth usually does not project above
the gums so that the animal appears to be toothless. No
teeth in upper jaw. Upperparts of body described as dark
slate black; lowerparts lighter; no special or
distinctive markings. External measurements of an adult
male reported by J.C. Moore: total length, 4.3 m;
circumference immediately in front of flipper, 1.85 m;
width across flukes, 91.5 cm; height of dorsal fin, 18.7
cm; distance from corner of eye to corner of mouth, 20
cm. Maximum known length, 5.45 m. Skulls of females are
larger than those of males so the assumption is that
females are also larger in body size than males.
Distribution in Texas.
Gervais beaked whales are known primarily from the
western North Atlantic. They are the most commonly
stranded beaked whale in the Gulf of Mexico with several
strandings on Texas beaches known. Although there are no
population estimates for these whales, they are thought
to be rare.
Habits. Almost nothing is known
about the life history of these whales. They are believed
to inhabit deep waters close to shore but little
information is available on movements. They are known to
feed on squid and fish.
Strandings of these whales are believed
to be associated with calving, which probably takes place
in shallow waters. A 4-meter female with a 2-meter calf
stranded in Jamaica and a pregnant female with a near
term fetus stranded along the Texas coast.
Specific data on the reproductive
habits are not available.
Illustration credit: Pieter