The Sperm Whale:
By Sam Van Nest
Description and Ecology:
Sperm whales are some of the largest animals in the world. Male sperm whales can grow up to 18 m long, weighing in at around 45 tons, while females grow up to 11 m long, and weigh a much smaller 15 tons. The largest recorded sperm whales were 22 m long and weighed 65 tons. Sperm whales have large box-shaped heads making up two thirds of their total body length. Found inside this abnormally larger head sits an
abnormally larger brain. In fact, sperm whales house the largest brain in the world. This brain is surrounded by a massive spermaceti organ. This organ containing spermaceti, is a waxy liquid which helps generate clicks for communication. Scientist believe this organ may help with the whales buoyancy and echolocation. An "S" shaped blowhole is positioned at the top front of their nose. Sperm whales have large powerful lower jaws with large cone shaped teeth and and small to no teeth on the top jaw. Behind their jaw are grooves allowing the throat to expand during eating. Sperm whales are covered with dark grey skin that is smoother around its head and turns to rough dimples as it moves towards its tail end. Small fins can also be found on either side of its body. Sperm whales do not have a pronounced dorsal fin but rather small bumps the largest of looking like a hump near the end of its back. Sperm whales generally swim in larger pods of 15-20 whales. These pods consist of young and female whales with few males. At the age of 5-20 male sperm whales will leave their maternal pods; joining different pods of males throughout their life until finally swimming solo near the end of its life. Sperm whales will live for around 70 years. These whales communicate with each other through clicks and have been found to protect there young or weak. Accounts have been reported of sperm whales teaming up to fight back predators like killer whales. Females will create a circle around their young to protect them. These mammals enjoy deep water but have return to the surface for air. They will spend anywhere from 45-90 minutes underwater and around 7 minutes near the surface. These whales can eat up to 1000kg of small fish and squid a day. Sperm whales mainly hunt around 2600 ft but will dive all the way to 10,000 ft to feast on giant squid.
Geographic and Population changes:Sperm whales are found in almost every ocean, but mostly stay clear of polar seas and coasts. They are found as far south as latitude 40 and as far north as latitude 50. When it comes to population size and structure little data is held certain. According to an estimate by Hal Whitehead in 2002 the population size was approximately 360,000. This is a huge decrease to the estimated 1,100,000 pre-hunted sperm whales. Though, these estimates are not that reliable. Due to just the sheer size of the ocean and lack of funds backing sperm whale population study's makes it very difficult to determine. A few things are known for certain though. Catch records before 1988 (prior to the end of whaling by IWC) showed a decline in sperm whale populations over the years. An estimated 68% of sperm whales were killed by whaling efforts. Sperm whales are still the most abundant whales found in oceans worldwide.
ESA Listing of Sperm Whales:
Sperm Whales were listed as an endangered species under the ESA on December 2, 1970. Since then several recovery plans have been published with the newest being published on December 21, 2010. The main cause of the listing of sperm whales was due to over whaling on a global scale. In 1988 the international whaling committee was created. IWC focused on protecting all whales around the world. IWC ended the commercial whale trade and allowed only japan to hunt and kill whales for scientific reasons. This largely brought an end to the sperm whales main threat. Other threats include collision with vessels, entanglement with fishing gear, habitat degradation, loss of prey due to climate change, and pollutants. The ESA recovery plan focuses on down listing the species from endangered to threatened and optimally delisting entirely. The ESA recovery plan emphasize the gathering of general information on sperm whales from population structure and discreetness to size. This is to help better understand the sperm whale and outline steps to take in its delisting. The fact that sperm whales travel through international borders freely means a large focus must be held on a multinational approach to management. This does complicate matters but is the only logical approach to take. Luckily the IWC has been focused on this task for nearly 3 decades. It is believed that sperm whale population are not declining and the big goal for ESA as of now is to properly recored the species abundance and structure.
Personal Actions:
The good that can be taken from this blog is that the Sperm Whale is no longer in any serious danger. Little personal action can be taken, but there is a few things you can do. If you ever come face to face with a sperm whale poacher, tell them to stop. Don't buy an spermatic wax candles or sperm oil. And if you still feel the urge to do more you can send a letter to Caroline Kennedy the us ambassador to Japan and ask if their is any thing she could do regarding the killing of Sperm whales for scientific purposes.
Here are some sites you can visit to find out more
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