Small Toothed Whales

1. Pygmy Killer Whale
2. Short-finned Pilot Whale
3. Long-finned Pilot Whale
4. Killer Whale
5. Melon-headed Whale
6. False Killer Whale

The subfamily Globicephalinae includes all of the smaller toothed whales and the Risso's dolphin. The Risso's dolphin has its own page and is treated with the rest of the oceanic dolphins. This page is devoted to the smaller toothed whales, including the Pygmy Killer Whale, the Melon-Headed Whale, the False Killer Whale, the Pilot Whales, and the Killer Whale. The term whale usually refers to size, not taxonomic classification. These whales are nearly always classified in the family Delphinidae, with the rest of the oceanic dolphins. They are more closely related to the dolphins than to any of the other whales. Some are, however, sometimes classified separately, as their appearance is quite different. Most species prefer deeper waters. Individuals of this subfamily are gregarious, and their groups are well structured. They may associate with other whales and dolphins, but they have also been known to prey on such smaller cetaceans. Most are easy to approach, notable exceptions being the pygmy killer whale and the melon-headed whale.

The pygmy killer whale is little-known and rarely seen in the wild. It has a very wide range, found almost anywhere in the deep waters of the tropics and subtropics. Its size is actually very small for what is considered a whale; it is about the same size as the average dolphin. It is possible to confuse this species with the melon-headed whale. There are many very small differences, but none is easy to see except at close range. The rule of thumb is that if the group has less than fifty individuals, it is probably a school of pygmy killer whales. The color is dark gray, often arranged in a cape similar to that many dolphins. In captivity, it is very aggressive towards both people and other cetaceans, deserving the name "killer" far more than killer whales. There is evidence that individuals in the wild eat dolphins. Although generally known to avoid boats, individuals have been seen bow-riding and wake-riding. Individuals are difficult to approach. On sunny days, groups have been seen logging. Spyhopping, lobtailing, and breaching have also been reported, but it is not as acrobatic as some other species. Pygmy killer whales are active swimmers and strand often.

In appearance, the short-finned pilot whale is almost identical to the long-finned pilot whale. At sea, it is very difficult to tell the difference between them. However, the flippers are of a different length, the two species have different numbers of teeth, and their skulls are shaped somewhat differently. The short-finned pilot whale prefers warmer waters, though, so there is virtually no overlap in their ranges. Groups have often been seen with bottlenose dolphins, but individuals attacking bottlenoses have also been observed. In general, these animals are gregarious, with whole pods having been seen logging. They allow boats to approach them. Lobtailing and spyhopping have sometimes been observed, as well as surfing on ocean swells. Short-finned pilot whales rarely breach. Feeding occurs mostly at night. In coloration, they range from jet black to dark gray. The sickle dorsal fin is on the foreward half of the body. The body is stocky and elongated.

The long-finned pilot whale is very difficult to distinguish from the short-finned pilot whale at sea, but the flippers are longer and the shape of the skull is somewhat different. Groups are often found in association with other ceatceans, such as the Minke whale, the common dolphin, the bottlenose dolphin, and the Atlantic white-sided dolphin. Although heavily exploited, this species still appears to be abundant. Pods sometimes sit motionless at the surface of the water. Bow-riding, lobtailing and spyhopping have all been observed. Breaching, although rare in adults, is common in juveniles. Long-finned pilot whales readily allow boats to approach them.

The killer whale is probably one of the easiest cetaceans to identify, with its unique and striking black and white coloration. With a robust, heavy body, it is the largest member of the family Delphinidae. A characteristic white patch exists behind the eye, and a gray saddle patch occurs behind the dorsal fin. The flippers are very large and paddle-shaped. The dorsal fin is triangular and very tall, reaching more than one meter in height. Of all the cetaceans, the killer whale has the largest range. It is found in nearly all waters of the world, although it is somewhat more common in polar waters than tropical waters. Groups consist of closely knit families called pods. Members stay together for life. Groups of closely related pods form clans, and each has its own dialect. At least two pods can combine into superpods of at least 150 individuals. Despite their rather menacing name, killer whales do not harm people, and aggression in the wild is quite rare. They are quite inquisitive and approachable. Although bow- and wake- riding are rare, breaching, lobtailing, flipper-slapping, and spyhopping are very common. Swimming speeds of up to 55 kilometers per hour have been recorded.

Two distinct forms have been identified: transients and residents. Transients form smaller pods of only one to seven individuals. They feed on mammals, make relatively few sounds, and their dorsal fins are more pointed and centrally located. Residents live in pods of between 5 and 25 individuals, and have far smaller home ranges, at least in the summer. Their diets consist of mainly fish, and they make many sounds. Unlike transients, their routes tend to be predictable; they do not change direction unpredictably. Dives are shorter as well, rarely exceeding four minutes.

Pods can be in a tight formation or spread out across more than one kilometer of ocean. Often entire groups surface and dive in unison. Their diets are very diverse, one of the most varied of all cetaceans. Some individuals have even been seen trying to feed on blue whales. Pods often coordinate their operations when hunting. One curious attribute is that pods seem to specialize, ignoring potential prey. Other species somehow sense that they are not in danger and assocate with the killer whales.

The melon-headed whale is not relatively well-known, although its widespread distribution includes all tropical and subtropical waters. It is known to associate with the Fraser's dolphin. In appearance, it is very similar to the pygmy killer whale, causing confusion between the two species. The differences are very difficult to see except when up close. The head is pointed and melon-shaped, and the body is slim. The flippers are long, and sharply pointed. Seen from above, the head is triangular. Although known to avoid boats, such observations come from areas where tuna boats are known to chase individuals, so the situation elsewhere may be different. Individuals have been known to bow-ride for short periods. Breaching has been recorded, as well as occasional spyhopping. Melon-headed whales are very social, and pods are generally larger than those of the pygmy killer whale. Pods are tightly packed and make frequent course changes. Melon-headed whales have been known to strand in large numbers.

Although the false killer whale has a wide distribution, it is rather uncommon. Individuals readily approach boats and are exceptionally active and playful, especially considering their large size. In captivity, specimens show less aggression than the pygmy killer whale. As attacks on humpback whale calves have been observed, it is believed that false killer whales prey on dolphins in the wild. Groups have been seen with bottlenose dolphins and other small cetaceans. Most pods are small, although groups of several hundred have been seen travelling together. The color is a uniform dark pigment, while the body is long and slim. The dorsal fin is prominent. The relatively large size of this animal distinguishes it from the pygmy killer whale and the melon-headed whale. Compared to female killer whales, false killer whales are slimmer and darker. At a distance, it is possible to confuse false killer whales with pilot whales, but the head and body are more slender, the dorsal fin more dolphinlike and the behavior more energetic. Swimming is fast and active, with individuals often lifting the heads and much of their bodies when breathing. Individuals are often seen surfacing with open mouths. Members of this species make sudden stops and sharp turns, especially when feeding. Individuals often approach boats to investigate, bow-ride, or wake-ride. Breaching is often observed, and individuals have been known to strand.

Bibliography

Carwardine, Mark. Eyewitness Handbooks: Whales, Dolphins, and Porpoises. New York: Dorling Kindersley Ltd., 1995.