Some stranded pygmy sperm whales have been found with plastic and other garbage blocking their guts. They could mistake debris in the deep scattering layer where they feed for prey and incidentally ingested it, leading to possible injury or death. Like many marine animals, pygmy sperm whales can ingest marine debris. They are vulnerable to vessel strikes throughout their range, but the risk is higher in some areas with heavy ship traffic.
Vessel StrikesĪccidental vessel strikes can injure or kill pygmy sperm whales. While they are no longer hunted in the United States, commercial harpoon fisheries in Indonesia, the Lesser Antilles, and Japan continue to take pygmy sperm whales. Historically, pygmy sperm whales were hunted during the 19th century. These conditions can lead to reduced reproductive success and death. Once entangled, they may swim for long distances dragging attached gear, potentially resulting in fatigue, compromised feeding ability, or severe injury. One of the main threats to pygmy sperm whales is becoming entangled or captured in commercial fishing gear such trap lines, pots, and gillnets. They do so by producing sounds from their melons (or foreheads) that reflect off the objects around them, which the whales perceive as echoes. This means that, like bats, pygmy sperm whales use sound to navigate and "see" the world around them. The whales use echolocation to locate prey.
They eat cephalopods (e.g., squid and octopus), crustaceans (e.g., crabs and shrimp), and fish. They typically feed in mid- and deep-water environments, as well as near the ocean floor. Pygmy sperm whales can dive at least 1,000 feet in search of food. The liquid creates a dark cloud in the water to help protect the whales when they feel threatened or are trying to escape predators. The whale can release more than 3 gallons of dark, reddish-brown liquid, or “ink,” from this sac. Each pygmy sperm whale has a sac filled with dark liquid in its intestine. Pygmy sperm whales’ use of the "squid tactic" makes them unique among other types of whales except dwarf sperm whales. While they do have a blowhole, they do not have a visible blow at the surface. They will slowly sink and disappear from view without showing their flukes before diving back into the water. When they are seen at the surface, they are usually either swimming slowly or lying still (also known as “logging”). Pygmy sperm whales spend very little time at the water’s surface and almost never approach vessels. These groups can vary based on age and sex, but little else is known about their social organization. Pygmy sperm whales are usually seen either alone or in small groups of six to seven individuals.
In the wild, it is very difficult to distinguish between them because they have similar appearances and geographic ranges. These two types of whales were not distinguished as separate species until 1966. Pygmy sperm whales can sometimes be confused with dwarf sperm whales, their closest relative. Their eyes are dark and bulging, and they have a marking behind the eye that is often called a false gill because it looks like a fish's gill cover or slit. They do not have teeth in their upper jaw but have 10 to 16 pairs of teeth in the lower jaw. Their underside is paler with white or pink tones.
#Hemisphere defense zone skin
Pygmy sperm whales have wrinkled skin and a brown to blue-gray back. Their head is sometimes described as shark-like because of their pointed snout and narrow, underslung lower jaw. While on the water’s surface, pygmy sperm whales have a low profile because their head and back are somewhat flat.
Each individual whale’s dorsal fin is a slightly different shape. Pygmy sperm whales have a small, compact body with a small and rounded dorsal fin.
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