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GERVAIS'S BEAKED WHALE
Mesoplodon europaeus (Gervais 1855)

Order Cetacea : Family Ziphiidae

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 the animal appears to be toothless. No teeth in upper jaw. Upperparts of body described as dark slate black; lower parts lighter; no special or distinctive markings. External measurements of an adult male reported by Joseph C. Moore (Field Museum of Natural History, Chicago): 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.

Mesoplodon europaeus

DISTRIBUTION. Gervais's beaked whales are known primarily from the western North Atlantic, but they are stranded in the Gulf of Mexico fairly commonly.

SUBSPECIES. Monotypic species.

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 Gervais's beaked whales are believed to be associated with calving, which probably takes place in shallow waters. A 4 m female with a 2 m calf stranded in Jamaica, and a pregnant female with a near-term fetus stranded along the Texas coast. Specific data on their reproductive habits are not available.

POPULATION STATUS. Rare; strandings and observations. Several strandings have been reported in the northern Gulf of Mexico, including on Texas beaches, and this is considered the most abundant of the Mesoplodon species in the region. Although there are no population estimates for Gervais's beaked whales, they are thought to be rare. It is virtually impossible to determine their status accurately, given the paucity of information.

CONSERVATION STATUS. Gervais's beaked whale is listed as threatened by the TPWD but is not included on the list of the USFWS. The IUCN lists its status as "data deficient" because there is little information on abundance and none on population trends.

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From The Mammals of Texas, Seventh Edition by David J. Schmidly and Robert D. Bradley, copyright © 1994, 2004, 2016.  Courtesy of the University of Texas Press.

Natural Science Research Laboratory