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.

Their acrobatic displays and tendencies to bow ride make false killer whales hard to miss if you are lucky enough to see one. Hawaii insular population numbers are predicted to be as low as 123 individuals, with only 46 capable of breeding. There is good news though. The insular false killer whale population was classified as an Endangered Species in 2012, meaning this population now has extra protection. Keep your eyes open. If you’re lucky you will see one of Hawaii’s very own false killer whales.

FURTHER READING:

  1. Protecting Hawaii’s False Killer Whale. Pacific Whale Foundation. Accessed October 8, 2015
  2. Baird, R. (2009). A review of false killer whales in Hawaiian waters: biology, status, and risk factors. US Marine Mammal Commission: 1-40.
  3. Chivers et al. (2009). Genetic Variation and Evidence for population structure in eastern North Pacific false killer whales. Canadian Journal of Zoology, 85: 783-94.

Written by Chelsea Brown

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.

Some think that tubercles serve as a sensory organ for the whale. It is thought that the single hair in each tubercle is used to detect temperature change in the water, the speed of the whale, and may even help to detect the presence of prey in the whale’s “blind spots.” Along with the idea that these tubercles serve a sensory purpose, comes an idea that tubercles assist with the hydrodynamics of the animal. It has been shown that these bumps increase lift and decrease drag in the water. Humpbacks are assumed to be one of the most acrobatic whales for their size. These tubercles may be a contributing factor for their agility.

Whale tubercles have inspired design ideas behind wind turbines, airplane wings and propellers. An energy company called WhalePower is applying tubercle-inspired bumps to numerous types of wind turbines and fans including industrial ceiling fans and computer fans to improve their efficiency, safety, and cost-effectiveness. These hairy humpback whales have inspired a new type of “greener” energy technology.

FURTHER READING:

  1. Forestell, P. H. and Kaufman, G. D. 2008. Humpbacks of Hawaiʻi: The Long Journey Back. Hawaii, USA. 216 pages.
  2. “Whalepower.” N.D. The Science.
  3. Canter, N. 2008. Humpback whales inspire new wind turbine technology.

Written by Stephanie Stack

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.

Right whales have hard white patches called callosities on their head, chin, and jaw. The unique pattern and coloration of these callosities help researchers to identify individuals.

Southern Right Whale head with callosities.

Southern Right Whale head with callosities.

While blue whales are generally bluish-grey in color, unique mottling patterns on both sides of the body near the dorsal fins can help distinguish between individuals.

Chiloe160206_0083

Blue Whale dorsal fin and markings. Photo courtesy of Elsa Cabrero, Centro de Conservación Cetacea.

Individual fin whales, also called finback whales, can be identified by the unique asymmetrical pattern of lighter colored chevrons and streaks on their back. The size and shape of the dorsal fin can also be used to distinguish between individuals.

Fin Whale aerial view. Photo courtesy of Wikipedia commons (Visit Greenland).

Fin Whale aerial view. Photo courtesy of Wikipedia commons (Visit Greenland).

FURTHER READING:

Written by Patrice Hostetter