Dwarf sperm whale
The dwarf sperm whale is the smallest species within the toothed whale family, measuring between 6.5 to 9 feet in length and weighing between 300 to 600 pounds. With distinctive square heads and a unique body structure, they are similar in appearance to the pygmy sperm whale. These whales typically inhabit small social groups, usually comprising 6 to 10 individuals, and are known for their strong social structures led by a dominant male. Dwarf sperm whales primarily feed on cuttlefish, squid, shrimp, crabs, and octopuses, possessing 16 to 24 teeth on their lower jaw. One notable defensive behavior is their ability to release a reddish-brown liquid when threatened, which helps obscure their escape. Mating takes place in warmer waters during the fall or winter, with a gestation period of 9 to 11 months, resulting in the birth of a single calf. In the wild, dwarf sperm whales can live for about 20 to 22 years, and they face natural predators such as killer whales.
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Dwarf sperm whale
The dwarf sperm whale is the smallest of more than 70 toothed whale species. It is similar to the Pygmy sperm whale (Kogiabreviceps).
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Kogiidae
Genus: Kogia
Species: Sima
Dwarf sperm whales have tail fins, small flippers, and small bumps across their lower backs. They have square heads with long, narrow mouths on the bottoms of their bodies. The dwarf sperm whale also has a blowhole on the front top of its head that it breathes through when it comes up for air. These whales sleep close to the water's surface with their blowholes above the water so they can breathe. Dwarf sperm whales grow to a head and tail length of 6 1/2 to 9 feet (2 to 2 3/4 meters) and weigh 300 to 600 pounds (136 to 272 kilograms).
Dwarf sperm whales live in small groups of 6 to 10 whales depending on their age and sex. There are groups of females and young led by a dominant male. Young males form bachelor groups and some adult males live alone. Dwarf sperm whales eat cuttlefish, squid, shrimp, crab, and octopus. They have 16 to 24 bottom teeth but only 6 on the upper jaw.
When frightened, dwarf sperm whales release 3 gallons (12 liters) of a reddish-brown liquid from a special sac in its intestines. This clouds the water and gives the small whale time to escape its attacker. This is called the "squid tactic." Killer whales (Orcinus orca) prey on the dwarf sperm whale.
The dwarf sperm whale's mating season occurs in the fall or winter. The whales swim from cooler waters toward the equator to mate. The males develop harems, or groups of females, to mate with. The gestation period (duration of pregnancy) is between 9 and 11 months. The females then give birth to one calf, or young whale.
The dwarf sperm whale has a life span of 20 to 22 years in the wild.
Bibliography
Chhoum, J., and R. Tang. "Kogia Sima." Animal Diversity Web, animaldiversity.org/accounts/Kogia‗sima. Accessed 5 Apr. 2024.
"Dwarf Sperm Whale." NOAA Fisheries, 15 Sept. 2022, www.fisheries.noaa.gov/species/dwarf-sperm-whale/overview. Accessed 5 Apr. 2024.