Hyperoodon ampullatus
northern bottlenose whale

The range of Hyperoodon ampullatus (the northern bottlenose whale) extends from the polar ice of the North Atlantic southwest to Long Island Sound and southeast to the Cape Verde Islands. (MacDonald, 1987; Minasian, Balcomb, and Foster, 1984)

H. ampullatus is most commonly found in waters at least 1000m deep and often forages at or near the north atlantic ice shelf in sheltered embayments during the spring and summer. (Reeves, Mitchell, and Whitehead, 1993)

Individuals of this species can reach up to 9.8m in length, but most are around 6.7-7.6m at the age of sexual maturity (7-14 years). They are sexually dimorphic, with males being up to 25% larger than females. The size of individuals in the Gully population (off Nova Scotia) is believed to be some 0.7m shorter than that of other Northern bottlenose whales. Individual whales may live up to 37 years (Herman 1980, MacDonald 1987, Whitehead et al. 1997a).

Northern bottlenose whales are varied in color, ranging from greenish-brown to chocolate and gray. Individuals may be blotted with patches of grayish-white and coloration is generally lighter on the flanks and underbelly, fading to a white or cream color. Young calves are generally chocolate colored in appearance (Evans 1987, Tinker 1988).

The body is long, robust and cylindrical and the beak is short, resembling a bottle in shape. Both sexes have large, protruding melons that are often vertical anteriorly in older animals and turn yellowish-white with age in males. The melon of the female is not as prominent as that of the male.The posteriorly-curved dorsal fin is 30-38cm in height and is located at a distance of 1/3 the total body length from the tail. The tail fluke lacks a medial notch and the flippers are small and pointed (Minasian et al. 1984, Tinker 1988).

The dentition of the species is highly reduced, with males possessing one or occasionally two pairs of short teeth in the tip of the lower jaw. These teeth never erupt in females, may never fully erupt in males, and often fall out with age (Minasian et al. 1984). (Herman, 1980; MacDonald, 1987; Whitehead et al., 1997a)

Northern bottlenose whales are generally found in groups of four to ten individuals, although group size may occasionally number as many as 25 individuals. Whalers observed that adult males sometimes travel separately from females and young males, and that this behavior occurs most commonly before and during the yearly migration. Data collected from The Gully population near Nova Scotia indicates that there may be long-term companionships between a small proportion of males and females (Harrison and Bryden 1988, Minasian et al. 1984, Reeves et al. 1993).

Hyperoodon ampullatus is generally migratory, spending the spring and early summer in the more northern latitudes and migrating south for the winter, and consists of at least two distinct populations. The larger population summers off Cape Chidley and across the mouth of the Hudson Straight to the mouth of Cumberland Sound along the 1000m depth contour and is widely distributed. The smaller population summers in a 20km x 8km area near the entrance of The Gully off the coast of Nova Scotia. Studies of The Gully population indicate that this population is likely non-migratory, remaining near Sable Island throughout the year. Strandings of Hyperoodon ampullatus off the coast of Europe in early fall indicate that many Northern bottlenose whales migrate to more southernly latitudes beginning in July (Reeves et al. 1993, Whitehead et al.1997a, Whitehead et al. 1997b).

These whales emit powerful ultrasonic clicks as well as low-intensity sounds which are audible to humans. Ultrasonic sounds are amplified in the melon and may serve in the echolocation of prey, especially in deep or murky water where there is little light penetration. Unlike other beaked whales, H. ampullatus is not prone to mass beachings (Evans 1987, MacDonald 1987, Reeves et al. 1993, Simmons and Hutchinson 1996).

Although the species' surface behavior is variable, H. ampullatus freqently approaches sluggish ships and may circle around them for an hour or more. This behavior, coupled with the tendancy for group members to aid an injured individual, made the Northern bottlenose whale a favorite target of whaling vessels (Harrison and Bryden 1988, Minasian et al. 1984, Reeves et al. 1993).

Hyperoodon ampullatus feeds primarily on squid (e.g. Gonatus fabricii), although sea cucumbers (Holothuroidea), herring (Clupea harrengus), cuttlefish (Sepiidae), sea stars (Asteroidea), and other benthic invertebrates supplement the diet. Utilizing a feeding method similar to that of Physeter macrocephalus (the sperm whale), northern bottlenose whales make deep, sustained dives to capture prey. Dives last up to 70min and diving depths range from 80 to 800m with a maximum recorded dive depth of 1453m. Breathing intervals of 10min are common between deep dives and individuals frequently resurface in close proximity to where a dive began (Herman 1980, Hooker and Baird 1999, Minasian et al. 1984, Reeves 1993, Walker 1975).

The Northen bottlenose whale was hunted for centuries for the spermaceti oil contained in its head and as a souce of food for native peoples. Scottish, English, and Norwegian whalers hunted H. ampullatus commercially from the mid-1800's until 1973. Because of its behavior of approaching large vessels and defending injured group members, whalers found Northern bottlenose whales easy to hunt. This whale's behavior and the fact that the spermaceti oil contained in its head was of almost equal quality to that of the Sperm whale resulted in overhunting and gross reductions in Northern bottlenosed whale populations around the turn of the century (Bloch et al. 1996, Reeves et al. 1993).

The IUCN relieved Hyperoodon ampullatus of its "vulnerable" listing in 1991, an currently lists it as "Lower Risk, subjec to continued conservation." COSEWIC (Committee on the Status of Endangered Wildlife in Canada) assigned the species to its "vulnerable" category in 1996. Though not listed under the U.S. Endangered Species Act, trade in northern bottlenose whales is restricted by CITES, the species is included in Appendix I. These whales have not been hunted commercially since 1973. (Elderkin, August 20,1998; Reeves, Mitchell, and Whitehead, 1993; Simmonds and Hutchinson, 1996)

Of all the Ziphiidae, Hyperoodon ampulatus is the most well-known and researched. It is closely related to H. planifrons, which inhabits the oceans of the southern hemisphere, and the two may have diverged only a few thousand years ago. Both species are very similar in external appearance, with H. ampullatus being slightly larger. The two species can be differentiated based on geographic distribution and the flatter maxillary crests of H. planifrons (Collete Hendricks 1997, Reeves 1993).

The early Miocene of Australia yields the first fossil evidence of Ziphiids, one of the most primitive families of whales (MacDonald 1987, Vaughn et al. 2000).