Dwarf Sperm Whale Population, Lifespan, Reproduction; How Do They Differ From Pygmy Whales

Dwarf sperm whales are often compared to pygmy sperm whales because they look identical. However, despite the similarities, there are distinct differences.

Dwarf Sperm Whale Facts

Dwarf sperm whales are toothed whales. The waxy spermaceti in the dwarf sperm whale's skull gave rise to its name. This oil-filled organ aids the whales in making sound. Dwarf sperm whales, like squids, can secrete a dark, ink-like substance that aids in predator avoidance.

Typically, dwarf sperm whales are observed individually or in tiny groups of no more than 16 animals. The age and sex composition of these groups can vary, but nothing else is known about how they are socially organized.

They rarely come close to boats and spend little time near the water's surface. Typically, they are either moving slowly or lying stationary (also known as logging) when they are observed at the surface. When they surface, their blows are hidden. Before reentering the water, they slowly descend and vanish from view without displaying their flukes.

Worldwide, temperate and tropical oceans are home to dwarf sperm whales. Dwarf sperm whales steer clear of the aircraft and vessels our scientists employ to gauge population size. Additionally, unless the sea and weather are exceptionally calm, it is challenging to see these whales when they surface to breathe due to their cryptic nature. Scientists hardly ever encounter dwarf sperm whales at sea as a result. Due to this, it is challenging to determine their minimal population size.

The lifespan of a dwarf sperm whale is 22 years. When they are 2.5 to 5 years old, they reach sexual maturity. Women give birth in the Southern Hemisphere between December and March. Women who have been pregnant for roughly a year may give birth. Calves are approximately 3.3 feet long and 30 pounds when they are born. After a year, they are weaned.

One of the major dangers to dwarf sperm whales is getting caught in or entangled in trap lines, pots, or other commercial fishing gear. Once tangled, they may swim a great distance while dragging linked gear, which could cause exhaustion, reduced eating ability, or serious injury.

Other threats include accidental vessel strikes, ingesting marine debris, underwater noise pollution, and illnesses like heart disease, immune system problems, and parasite infestations.

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Dwarf Sperm Whales Vs. Pygmy Sperm Whales

The dwarf sperm whale resembles the pygmy sperm whale greatly. Since the two species are so frequently mistaken, telling them apart in the field can be exceedingly challenging. Due to the scarcity of knowledge and the mystery surrounding both species' debut at sea, nothing is known about them. However, one of their distinct differences is that dwarf sperm whales have larger dorsal fins that are over 5 percent of their body length and set nearer the middle of the back. Additionally, the dwarf sperm whale has a shark-like profile like its congener, albeit it has a more pointed snout than the pygmy sperm whale. Its lower jaw includes 8 to 11 (sometimes up to 13) pairs of teeth, and occasionally the upper jaw bears teeth.

Also, dwarf sperm whales can grow to shorter maximum lengths. However, many observations of Kogia whales at sea may not be able to be identified to species because sizes overlap and dorsal fins vary in size and location.