Blog Tags: Sperm Whales
Plastic is one of the most common pollutants that end up in the ocean, but the properties that make it ideal for shopping make it deadly to marine life.
Plastics are durable and do not decompose easily, which means they can stay in the ocean for decades. And because they are so lightweight, plastics can float in the ocean where sea turtles and marine birds can get entangled or even ingest them by mistake. For example, plastic bags in the ocean closely resemble jellyfish, which are a common food for sea turtles.
Plastic can also have serious effects on marine mammals, including sperm whales which are some of the world’s smartest animals – possessing the largest brain of any known species.
Sperm whales typically feed on squid, sometimes diving more than a mile below the ocean’s surface to find food. But plastic trash is becoming more and more a part of the whales’ diets. Each year, sperm whales eat more than 100 million tons of seafood using suction, which makes them more vulnerable to ingesting plastic. And because sperm whales are at the top of the food chain, they are the most likely to be affected by pollution.
Editor’s Note: Guest blogger Shane Gero is a Ph.D. candidate at Dalhousie University in Nova Scotia and a lead researcher for the Dominica Sperm Whale Project.
I met Enigma when he was only a few months old. He was about three meters long and probably weighed over a ton.
That’s about average for a newborn sperm whale. When he reaches full size, in about 25 years, Enigma might be as long as 18 meters and weigh over 50 tons.
I have been following Enigma’s family since before he was born. I have spent literally thousands of hours at sea following them and about 20 other families of sperm whales which live in the eastern Caribbean Sea.
It has really been the first time that anyone has come to know these leviathans from the deep as individuals with personalities, as brothers and sisters or as mothers and babysitters, and as a community of families each with their own ways of doing things, their own dialects, and their own cultures.
Sperm whale relationships are very much like our social lives -- more so than many might like to admit. The main difference is the most obvious, they live in the ocean. You see, most of the ocean is actually dark. Only a thin layer at the surface gets any light from the sun. For a sperm whale, life is really in the darkness of the deep.
I jokingly call them “surfacers” rather than “divers” because an adult female, like Enigma’s mother Mysterio, will spend over 80 percent of her life in the darkness of the deep ocean feeding. She will only spend about 10 to 15 minutes of every hour in the part of the ocean that sunlight touches and where I can observe her interacting with other members of her family.
As a result, while Mysterio’s eyesight is good both above and below the water, her world is dominated by sound. Just like bats, sperm whales have evolved a system of echolocation to “see” in the dark. Their unique nose, which houses the most powerful natural sonar system, has allowed them to exploit the deepest parts of the ocean that very few other mammals can, and as a result has made them a significant part of the ocean ecosystem. Globally, sperm whales can eat as much squid as all of humanity’s fisheries combined.
On this hump day, a few cetaceous stories for your perusal:
As you've probably heard, the team behind Sunday’s Oscar-winning documentary “The Cove” exposed Santa Monica sushi restaurant The Hump for serving illegal whale meat. The possession or sale of marine mammals -- in this case, the endangered sei whale -- is a violation of the Marine Mammal Protection Act, and can lead to a year in prison and a fine of $20,000.
And on the brighter side, the BBC has a remarkable slideshow of images showing a sperm whale surface feeding off the coast of New Zealand. Surface feeding is uncommon for sperm whales, who usually hunt many meters below the sea’s surface -- this individual must have been pretty hungry.
The researchers have evidence of the whales staying together over several months in the Gulf of Mexico. And their behavior varied with each deep dive, indicating that they alternate roles to spread out the physiological demand of the 1,000-meter dives.
One researcher said that the some whales appeared to guard the bottom of a squid bait ball, while others took advantage of the center of the ball.
Other research has suggested dolphins may exhibit herding behavior, but this is the first evidence in sperm whales; some scientists remain skeptical.
Just remember, whales: there is no "I" in "team."
Don't you hate when you're at a party or restaurant, and even without music on, the room grows louder and louder and louder? Until you can barely hear the person standing right next to you? New research shows that sperm whales have evolved to circumvent this cocktail party conundrum.
According to the scientists, whose work will be presented at the Acoustical Society of America next week, the whales are polite conversationalists -- they make a specific effort to keep their calls from overlapping by changing the intervals between their echolocating clicks.
Perhaps humans can try this. It might go something like this:
"Would you - click - like an hors d'oeuvre - click?"
"Yes, one - click - mushroom puff - click - please."
And in other acoustic findings, researchers have discovered the first known instances of male humpback whales singing to one another, similar to songbirds. Whether the whale songs are macho seduction tunes -- like male birdsongs -- is still unclear.
What is clear is that there's a lot we don't know about what's being said and sung under the sea.
Sperm whales are named for the waxy oil in their head, spermaceti. Used in many industries ranging from cosmetics to automotive, spermaceti drove whalers to target sperm whales and they are now listed as threatened by the International Union for Conservation of Nature and Natural Resources. Due to their size, however, sperm whales have been known to fight back, famously attacking and sinking the whaling ship, Essex, the ship Moby Dick is based upon. Learn more about these large predators and other animals in the Creature Corner.
When I usually read about theft and the sea, I think of overfishing and depleted natural resources. But this time around, it is a hungry predator taking advantage. Check out this video on National Geographic Kids and get ready for a surprise around the 35 second mark. One particularly smart sperm whale has learned how to shake fish free of lines without injury. Perhaps if he had enough food in the open sea, he wouldn’t have to resort to such tactics.
- Sea Turtles Can Get the Bends after Capture in Fishing Gear, Says New Study Posted Tue, November 25, 2014
- Ocean Roundup: North Atlantic Right Whales Calving in Southeast, New Shark Repellent Tested in South Africa, and More Posted Thu, November 20, 2014
- Ocean Roundup: Dolphins Use Whistles as Names, Conservationists Call for Removal of Queensland Shark Nets, and More Posted Mon, November 24, 2014
- Creature Feature: Ocean Sunfish Posted Thu, November 20, 2014
- Oceana in Chile Submits Recommendations for Lowering Common Hake Catch Quotas Posted Mon, November 24, 2014