FACT OF THE WEEK: False Killer Whales Call Hawaii Home

MORE ON THIS: False killer whales, while a globally distributed species, have a special tie to Maui and the four-island region. Recent research has found that a very small group of this odontocete, or toothed whale species,  calls Hawaiian waters home, making them genetically different from offshore groups. This makes this population especially interesting because false killer whales are generally thought to prefer deep ocean environments far from any land.

Genetic tests were completed on samples collected from groups of false killer whales around the main Hawaiian islands and locations throughout the North Pacific. Researchers found samples collected from individual whales close to the Islands were most genetically unique when compared to samples from whales in the Pacific Ocean, Panama and Mexico. The uniqueness of the samples indicates there are two separate populations; an inshore population and an offshore population.

Continue reading

FACT OF THE WEEK: Hairy Humpback Whales

FACT OF THE WEEK: Humpback whales have hair!

MORE ON THIS: You probably know that whales and dolphins are marine mammals. Marine mammals, like terrestrial or land mammals, must have a certain set of characteristics to be called mammals – these include giving birth to live young and having hairs on their bodies. But where are the hairs on whales?

In fact, you have probably seen the hairs on humpback whales and not known what they were. The bumps on the rostrum, or head, and the pectoral fins of a humpback whale are, in fact, hair follicles. Called “tubercles,” these fist-sized bumps contain one hair follicle each, connected to a set of sensitive nerves. Why do humpback whales have these sensitive whiskers? There are multiple speculative theories in scientific literature, but no consensus.

Continue reading

FACT OF THE WEEK: The Name Game

FACT OF THE WEEK: Bottlenose dolphins may address each other by name!

MORE ON THIS: Recent research has suggested that bottlenose dolphins have individually unique signature whistles that are equivalent to human names. During the first few months of life, a dolphin will develop its own signature whistle made up of a series of sounds and notes. Dolphins will also adopt the signature whistle of other dolphins in the pod to identify and communicate with different individuals, specifically close associates or those with strong social bonds. When a dolphin emits its own signature whistle, a  dolphin that is a close associate will reply with a copied version of the whistle with a few subtle alterations that differentiates the signature whistle from the copied whistle. This allows the second dolphin to relay information back to the first dolphin; the alterations to the whistle may also give information about who the second dolphin is.

Signature whistles httpwww.cell.comcmsattachment20079513612030487757gr2.jpg

Image from: Janik, V.M. 2013. Cognitive skills in bottlenose dolphin communication. Trends in Cognitive Sciences 17(4): 157 – 159.

Many species of dolphins live in fission-fusion societies, this means that the size and composition of the pod will change as time passes. When pods merge together, vocal signatures are exchanged in order to learn about the identities of individual members of the new pod. These exchanges are generally repeated several times during the interaction to either improve the probability of correct identification, or provide additional information with each exchange.

FURTHER READING:

Written by Patrice Hostetter

What do Whales and Cats have in common?

Marine mammals have a reflective layer behind the retina of their eye called tapetum lucidum, which is Latin for “bright tapestry”. It is this same reflective layer that causes the eyes of cats to glow at night. This layer enhances the ability of an animal to see under low light conditions by reflecting light back through the retina a second time, making the most of available light.

Cat eye reflection from camera flash. Photo courtesy of Shanoaleigh Roseby.

Cat eye reflection from camera flash. Photo courtesy of Shanoaleigh Roseby.

The retina of baleen whale’s eyes contains mostly rod cells, which are sensitive to low intensity light, while cone cells, which distinguish between different colors and are most sensitive to bright light, are less abundant. This means that whales are most likely to see the world in shades of grey.

Humpback Whale Eye

Humpback Whale Eye

FACT OF THE WEEK: Whale Tale

FACT OF THE WEEK: The underside of a whale’s tail, called the flukes, is not the only characteristic that can be used to photo-identify baleen whales.

MORE ON THIS: You may already know that humpback whales have individually unique tail flukes, like a human fingerprint, and can be identified by photographing these. In addition, each humpback whale also has a unique dorsal fin that allows researchers to track and study individual whales using photo-identification techniques. But did you know that other species of baleen whales are identified using other body parts?

humpback whale fluke (PWF-Hawaii 2013)

Humpback whale flukes. Photographed under NOAA permit # 16479.

Gray whales don’t actually have a dorsal fin; instead they have a series of “knuckles” along their back. Researchers can use the shape of these knuckles, as well as mottling, scarring, and barnacle patterns on the whale’s back to identify individuals.

Grey Whale dorsal ridge - front view. Photo courtesy of Flickr user Minette Layne.

Grey Whale dorsal ridge – front view. Photo courtesy of Flickr user Minette Layne.

Minke whales are identified using nicks or notches in their dorsal fins, or by unusual dorsal fin shape, similar to photo-identification in dolphins. They can also be identified on the basis of lateral body pigmentation.

Minke Whale dorsal fin with notch. Photo courtesy of Stephanie Stack.

Minke Whale dorsal fin with notch. Photo courtesy of Stephanie Stack.

Continue reading