Posts Tagged ‘dolphin’


Researchers found the first known hybrid between a rough-toothed dolphin and a melon-headed whale near Kauai, Hawaii.


Rough-toothed dolphins.


Melon-headed whales.

By Jessie Yeung

Scientists from the Cascadia Research Collective have discovered a rare dolphin-whale hybrid off the coast of Kauai, Hawaii, according to a report published last week.

The marine mammal monitoring program, funded by the US Navy, first spotted the animal in August 2017. The team tagged various species, including commonly seen rough-toothed dolphins and rarer melon-headed whales.
However, researchers soon noticed that one tagged animal that looked a little odd. Although it had a typical melon-headed whale’s dorsal fin shape and dorsal cape, it was also blotchy in pigmentation and had a sloping forehead, more reminiscent of a rough-toothed dolphin.

A genetic sample soon confirmed their suspicions: it was a hybrid of the two species, the first to ever be found.The cross-species hybridization may seem bizarre, but is made possible by the fact that melon-headed whales aren’t actually whales. They belong to the Delphinidae family, otherwise known as oceanic dolphins, which also includes orcas and two species of pilot whales.

It also isn’t the first discovery of hybridization in the family
— there have also been cases of bottlenose dolphin/false killer whale (Pseudorca crassidens) hybrids, known as Wolphins, and common/bottlenose dolphin hybrids.

This is the first confirmed hybrid between rough-toothed dolphins and melon-headed whales. However, though it’s an exciting discovery, researchers point out it is not, as commonly thought, a new species.

“While hybridization can at times lead to new species, most of the time this does not happen,” Cascadia researcher Robin Baird told CNN, pointing that there was only a single hybrid found this time.

Some hybrid animals, such as the mule — a hybrid of a male donkey and female horse — are mostly sterile and therefore cannot propagate easily.

The dolphin-whale hybridization is especially surprising in this region, as a sighting of melon-headed whales had never before been confirmed near the Pacific Missile Range Facility (PMRF) navy base.

The hybrid was only traveling with one companion — a melon-headed whale. This, too was unusual, given that melon-headed whales typically travel in groups of 200-300. The solitary pair were “found associating with rough-toothed dolphins,” the report read.

The odd pair and their closeness to the other dolphins have led the researchers to speculate that the accompanying melon-headed whale is the hybrid’s mother.
The research team will return to Kauai next week, hoping to confirm their theory.

“If we were lucky enough to find the pair again, we would try to get a biopsy sample of the accompanying melon-headed whale, to see whether it might be the mother of the hybrid, as well as get underwater images of the hybrid to better assess morphological differences from the parent species,” said Baird.

The US Navy is required to monitor these species as part of the Marine Mammal Protection Act and the Endangered Species Act.

They do so through the Cascadia Research Collective, which conducts photo identification, genetic analyzes, and acoustic monitoring to determine the abundance of odontocetes, also known as toothed whales.

https://www.cnn.com/2018/07/30/us/dolphin-whale-hybrid-intl/index.html

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By Ben Westcott

A conversation between dolphins may have been recorded by scientists for the first time, a Russian researcher claims.

Two adult Black Sea bottlenose dolphins, named Yasha and Yana, didn’t interrupt each other during an interaction taped by scientists and may have formed words and sentences with a series of pulses, Vyacheslav Ryabov says in a new paper.

“Essentially, this exchange resembles a conversation between two people,” Ryabov said.

Joshua Smith, a research fellow at Murdoch University Cetacean Research Unit, says there will need to be more research before scientists can be sure whether dolphins are chatting.

“I think it’s very early days to be drawing conclusions that the dolphins are using signals in a kind of language context, similar to humans,” he told CNN.

There are two different types of noises dolphins use for communication, whistles and clicks, also known as pulses.

Using new recording techniques, Ryabov separated the individual “non coherent pulses” the two dolphins made and theorized each pulse was a word in the dolphins’ language, while a collection of pulses is a sentence.

“As this language exhibits all the design features present in the human spoken language, this indicates a high level of intelligence and consciousness in dolphins,” he said in the paper, which was published in the St. Petersburg Polytechnical University Journal: Physics and Mathematics last month.

“Their language can be ostensibly considered a high developed spoken language.”

In his paper, Ryabov calls for humans to create a device by which human beings can communicate with dolphins.

“Humans must take the first step to establish relationships with the first intelligent inhabitants of the planet Earth by creating devices capable of overcoming the barriers that stand in the way of … communications between dolphins and people,” he said.

Smith said while the results were an exciting advance in the under-researched field of dolphin communication, the results first needed to be replicated in open water environments.

“If we boil it down we pretty much have two animals in an artificial environment where reverberations are a problem … It wouldn’t make much sense for animals (in a small area) to make sounds over each other because they wouldn’t get much (sonar) information,” he said.

“It would be nice to see a variety of alternate explanations to this rather than the one they’re settling on.”

http://www.cnn.com/2016/09/13/europe/dolphin-language-conversation-research/index.html

Animals often have symbiotic relationships. Egrets hang out on the backs of many large animals, picking parasites in exchange for free food and transportation. Plovers act as dentists, eating the leftover food inside the mouths of crocodiles.

But this relationship is baffling. Sometimes dolphins hitch rides on the backs of humpback whales — and it’s very possible that the only thing either party is getting out of it is a little bit of fun.

The above photo of a dolphin riding piggyback on a whale garnered lots of attention when it was posted a few years ago on Facebook by the Whale and Dolphin People Project and it’s making the rounds again this week.

According to the description that came with the photo:

“This is one of the strangest cetacean photos I’ve ever seen. It was taken by Lori Mazzuca in Hawaii. She said that the dolphin and humpback whale were playing gently together. The game seemed to be about how long the dolphin could stay atop the whale’s head while the whale swam. When the dolphin finally slipped off, it joined another dolphin and they began to leap with joy.”
The creature lovers at Discovery News were a little suspicious that the image may have been Photoshopped or altered in some way. So they asked some experts to weigh in.

“Both dolphins and humpback whales can be extremely playful with each other and other species,” said Diana Reiss, a cognitive psychologist and dolphin researcher at Hunter College in New York. “It is very possible that this is play, but without seeing it first-hand, I really don’t know.”

“Based on the description, I believe play would be the best explanation,” agreed Ken Ramirez, vice president of animal care and training at Shedd Aquarium in Chicago. “If this were a video, there would be far more information to allow for better interpretation. But it is believed that the ‘surfing’ or bow riding that dolphins exhibit in front of boats may have had its genesis in riding in front or in the wake of big whales.

“What we may be seeing here is that type of surfing, but in this case the whale chose to give the dolphin a different type of ride.”

It’s not quite as clear as the image above, but here’s a video taken in Maui, Hawaii, of a bottlenose dolphin allegedly riding on a humpback whale.

Read more: http://www.mnn.com/earth-matters/animals/stories/why-do-dolphins-hitch-rides-whales#ixzz3gI81gckF

Tastes are a privilege. The oral sensations not only satisfy foodies, but also on a primal level, protect animals from toxic substances. Yet cetaceans—whales and dolphins—may lack this crucial ability, according to a new study. Mutations in a cetacean ancestor obliterated their basic machinery for four of the five primary tastes, making them the first group of mammals to have lost the majority of this sensory system.

The five primary tastes are sweet, bitter, umami (savory), sour, and salty. These flavors are recognized by taste receptors—proteins that coat neurons embedded in the tongue. For the most part, taste receptor genes present across all vertebrates.

Except, it seems, cetaceans. Researchers uncovered a massive loss of taste receptors in these animals by screening the genomes of 15 species. The investigation spanned the two major lineages of cetaceans: Krill-loving baleen whales—such as bowheads and minkes—were surveyed along with those with teeth, like bottlenose dolphins and sperm whales.

The taste genes weren’t gone per se, but were irreparably damaged by mutations, the team reports online this month in Genome Biology and Evolution. Genes encode proteins, which in turn execute certain functions in cells. Certain errors in the code can derail protein production—at which point the gene becomes a “pseudogene” or a lingering shell of a trait forgotten. Identical pseudogene corpses were discovered across the different cetacean species for sweet, bitter, umami, and sour taste receptors. Salty tastes were the only exception.

“The loss of bitter taste is a complete surprise, because natural toxins typically taste bitter,” says zoologist Huabin Zhao of Wuhan University in China who led the study. All whales likely descend from raccoon-esque raoellids, a group of herbivorous land mammals that transitioned to the sea where they became fish eaters. Plants range in flavors—from sugary apples to tart, poisonous rhubarb leaves—and to survive, primitive animals learned the taste cues that signal whether food is delicious or dangerous. Based on the findings, taste dissipated after this common ancestor became fully aquatic—53 million years ago—but before the group split 36 million years ago into toothed and baleen whales.

“Pseudogenes arise when a trait is no longer needed,” says evolutionary biologist Jianzhi Zhang of the University of Michigan, Ann Arbor, who was not involved in the study. “So it still raises the question as to why whales could afford to lose four of the five primary tastes.” The retention of salty taste receptors suggests that they have other vital roles, such as maintaining sodium levels and blood pressure.

But dulled taste perception might be dangerous if noxious substances spill into the water. Orcas have unwittingly migrated into oil spills, while algal toxins created by fertilizer runoff consistently seep into the fish prey of dolphins living off the Florida coast.

“When you have a sense of taste, it dictates whether you swallow or not,” says Danielle Reed, a geneticist at the Monell Chemical Senses Center in Philadelphia, Pennsylvania. She was not involved with the current work, but co-authored a 2012 paper that found the first genetic inklings that umami and sweet taste receptors were missing in cetaceans, albeit in only one species—bottlenose dolphins.

Flavors are typically released by chewing, but cetaceans tend to swallow their food whole. “The message seems clear. If you don’t chew your food and prefer swallowing food whole, then taste really becomes irrelevant,” Reed says.

http://news.sciencemag.org/biology/2014/05/whales-cant-taste-anything-salt

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.