Sperm whales choose Dominica’s waters as their only year-round home, and the likelihood of seeing them is always surprisingly good, as whales and dolphins live close to shore no matter the weather.
Titans of the deep
Sperm whales are the largest toothed marine species in the world, with the largest brains and dive the deepest into the ocean, in search of squids to eat.
They received their names by a waxy substance, called spermaceti, was found in their heads. Spermaceti is an oil sac that assists the whales to focus on sound. Their scientific name is cachalot (Physeter marcocephalus).
Sperm whales are now classified as endangered under the Endangered Species Act and slowly recovering from decades of being hunted. From 1800 to 1987, Sperm whales were hunted for the commercial industry, their spermaceti was a key ingredient to make oil lamps, lubricants and candles.
Also known as the ‘Titans of the Deep’ due to their enormous size can reach up to 70 feet (21 metres) long and can weigh up to 60 tons (54000 Kilograms). They are deep grey in colour, with a hump than a dorsal fin, and triangular shaped tails, or flukes. They have wrinkled skin behind their heads to increase surface area that makes up a third of their total body length. This makes it easier to loss more heat.
Sperm whales have a distinct s-shaped blowhole, located on the top left side of their heads.
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Dominica is their special home
Sperm whales only reside around Dominica, where there’s an opportunity to view them in year-round whale watching activities. Most sperm whale sighting occur between November and March and are usually spotted at Scotts Head, Roseau, Layou, and Point Round. Adventurers have the chance to experience to snorkel with sperm whales, with the guide of expert divers into Dominica’s underwater sea life.
A short boat ride across Dominica’s turquoise blue sea, allows divers to have clear views of these magnificent sperm whales and dolphins. A group of sperm whales are called “pods”, and typically between 15 to 20 whales that consist of females and their young. Male sperm whales may be found swimming alone or move from group to group.
Interesting facts about these amazing sperm whales
Sperm whales can live up to 70 years. The female whales start ovulating from nine years old, and the oldest recorded pregnancy was a 41-years-old female whale. Mating period usually occurs in spring and summer seasons. Females can give birth every 3 to 5 years, after carrying their young for 14 to 16 months.
Despite being large predators, these magnificent whales sleep for a brief period each night floating between 15-20 minutes at a time, sleep vertically and do not breathe during their nap time. Whilst asleep, their heads are at the surface or just above the surface.
Hunting for food
Sperm whales hunt squid using echolocation that can reach 230 dB underwater, making them the loudest animals on earth. Their pray can become disabled or killed from their sound alone. The use clicking sounds called “codas”, scientists believe that each whale has unique coda to communicate
These whales have claimed their position as world-class deep-sea divers. It is recorded that the sperm whale can descend into depths of up to 3,280 feet. When in search of food they can dive holding their breath for 90 minutes at a time.
Sperm whales can be found constantly eating. They can consume 2 tons of food in a day that is equivalent to 3% of their body weight. In 1977, it was estimated that a pod of whales ate more than 100 million tons of squid in that year.
Largest brain size of all mammals
A sperm whale brain has a measured volume of 8,000 cubic centimetres and average weight of 17 pounds (7 kilograms). The largest known brain of any mammal, both extinct and living.
If you’re travelling to the Caribbean any time soon, add this to your bucket list of things to do!