Whales are some of the biggest animals in the sea, but their massive size doesn't exclude them from predation. One of the biggest predatory threats to whales is actually other whales -- namely killer whales, or orcas. Popular as a tourist attraction, killer whales are just as deadly as great white sharks -- but much, much smarter.
Fight or Flight
Like almost every other animal, whales have a "fight or flight" response to being attacked. When being hunted by killer whales in arctic waters, slow-swimming belugas will use sea ice to evade their fellow cetaceans. Grey whales, on the other hand, have been known to fight back against their attackers. The grey whale earned the nickname "devilfish" during whaling times because it had a reputation for ramming vessels that attacked the whale itself or its calves.
Both anecdotal evidence and scientific research have indicated that whales also band together when they feel threatened. In 1997, a group of scientists from the National Oceanic and Atmospheric Administration witnessed a group of nine sperm whales being attacked by a pod of killer whales. The scientists said the sperm whales attempted to beat back their attackers by arranging in a circular formation, with their heads pointed inward, and using their tail fins to swipe at the orcas. They were ultimately unsuccessful. A 2013 study in the journal Scientific Reports by a team of European scientists found male sperm whales become increasingly social and vocal upon hearing killer whale songs.
In addition to being a protective layer against would-be predators, blubber affords all whales protection against hypothermia. Heat loss in water is 27 times greater than on land and blubber helps to keep a whale's body heat inside the animal. This fatty layer comprises 27 percent of the massive blue whale's total body weight. Blubber is actually comprised of three layers: the dermis, epidermis and hypodermal tissue. While the dermis and epidermis of a blue whale are similar to what is found in other mammals, the hypodermal tissue is mostly made up of fat cells and is similar to the layer of fat found underneath the skin of a pig.
The Bizarre Defense Mechanism of the Pygmy Sperm Whale
Any discussion about the defense mechanisms of whales is not complete without mentioning the pygmy sperm whale. Only about twice the size of the average human when fully mature, pygmy sperm whales tend to live their entire lives offshore at depths of between 1,300 and 3,000 feet. When these modestly sized whales are under attack, they defend themselves by releasing fecal material into the water and swirling it around with their fins. The whales are undoubtedly banking on the notion that swimming through a cloud of feces will put off any predator's appetite.