WHALE TRUST MAUI

Conducting, Promoting and Supporting Whale Research and Education in Maui, Hawai‘i

All About Whales

New Function for Bubbles Observed in Hawaiian Humpback Breeding Grounds

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Read Full Paper: Female Humpback Whale Positions Genital-Mammary Area to Intercept Bubbles Emitted by Males on the Hawaiian Breeding Grounds

Aquatic Mammals 2022, 48(6), 617-620, DOI 10.1578/AM.48.6.2022.617

Humpback whales are well known for their use of bubbles. One of their most widely documented uses occurs in a feeding context where either an individual or group of humpbacks utilize a variety of bubble-based tactics to net, trap, and herd their prey. 

Flip Nicklin/Minden Pictures. NMFS Permit #19225.

We report a different use of bubbles by humpbacks in the Hawaiian breeding grounds on multiple occasions between 2000 and 2003 in the Au’au Channel off West Maui, Hawaii. Our research team at Whale Trust filmed a 14-minute interaction between multiple males and one female in which the males circled the female and produced bubbles directed toward the female’s swollen genital region. The female appeared to tolerate and possibly aid in the reception of these bubbles. We have observed similar scenarios on multiple other occasions as well.

These observations are intriguing and reveal a new dimension to male-female interactions on the breeding grounds. There are two primary contexts within which to consider this behavior:

 (1) To maximize mating opportunities – Mating/Estrus Female 

  • In the scenario that the female was present to mate and in estrus (a recurring state of sexual receptivity and fertility in many female mammals) this could explain her receptiveness of the males and the males’ attention toward the female. 
  • In this case, we could speculate that this interaction may serve a sexual purpose such as helping stimulate the female prior to intercourse or assisting in the release of chemical cues that could signal to the male her reproductive status and readiness to mate. 

(2) To ensure successful birth and calf development – Late Pregnant Female

  • In the scenario that the female present was a late pregnant female and about to give birth, this could explain her extended girth, swollen genitals, and even the presence of multiple males around a birthing female. 
  • In this case, we could speculate that the bubbles could stimulate the release of hormones, such as oxytocin, known to be vital in the birthing process.
  • The pressing question is, if this is the correct case, why are males involved and not females? What is in it for the males?

While interpretation of the use of bubbles in our recording and their exact meaning remains speculative, it does show the complex and wide array of bubble use in humpback whales. Future research aimed at understanding the hormonal state of male and female humpbacks within different social groups and situations on breeding grounds should provide the insight needed to determine the correct context for the behavior patterns described here. 

Is The Ocean Blue? Not to whales.

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By Jim Maxwell, Ph.D.

ONE FISH, TWO FISH, RED FISH, BLUE FISH!

We don’t know if whales can count but we do know they can’t tell one color of fish from another.  Whales are color blind. Why cetaceans are color blind remains somewhat of a mystery. Except for some nocturnal species, virtually all land mammals have color vision and, presumably, so did the ancient ancestors of whales from which they evolved (the closest living animal to the whale is the semi-aquatic hippopotamus). The lack of color vision in cetaceans must have occurred early in their evolutionary development because all cetaceans studied so far, whether toothed or baleen, have been found to be essentially color blind. Interestingly, pinnipeds (seals) are also color blind.  Since seals and whales are not closely related, scientist think that the loss of color vision must have served some advantage millions of years ago when their ancestors lived in coastal environments.

In order to understand color vision in whales, it helps to know a little bit about how the visual system works in humans and most other mammals. The retina in the back of the eye contains two types of light receptors, cones and rods, that convert light energy into electrical signals that can be further processed by the brain. Cones are active in the light and are responsible for color vision and the perception of detail. Rods are much more sensitive to light and take over for the cones in dim light but rods are typically not involved in color vision.

Most land mammals have two types of cones.  One type of cone is most sensitive to the red-green part of the color spectrum (long to medium wavelengths of light) and the other is most sensitive to the blue (short wavelength) part of the spectrum. Somewhere along the line, most odontocetes (toothed whales) and seals, through genetic mutations, lost the functionality of short-wavelength-sensitive receptors (S-cones) leaving them with only the long to medium wavelength cones (L-cones) and rods. Because the brain relies on a comparison of the signals coming from different types of cones to produce the perception of color, having only one cone type leaves these marine mammals essentially color blind, or, “L-cone monochromats” in the jargon of vision science.

Studies within the past five years have indicated that many, and possibly even all, mysticetes (baleen whales) have not only lost the functionality of S-cones but the functionality of L-cones as well, making them totally reliant on rod photoreceptors for vision (and hence called “rod monochromats”). Rod monochromacy is rare in terrestrial mammals and results in very poor eyesight. By comparison, humans and many other primates have very good color vision having three types of cones.  Most other mammals (and color-blind humans) have only two types of cones and consequently cannot distinguish red from green. We do not have the best color discrimination in the animal kingdom by any means. Some reptiles, including some species of turtles, birds and fish have four types of cones and can see into the ultraviolet part of the spectrum not normally visible to humans.

Needless to say, whales do have functional vision even if it is in shades of gray, it’s just that they rely more on contrast than on color. How well whales see is hard to determine with any precision but it is certainly much inferior to the average human. The acuity of cetaceans, that is, their ability to discern detail, has been studied in trained dolphins and has also been estimated in several other species of toothed and baleen whales by examining the anatomy of their eyes and retinas. But that is a story for another blog.

Updated 4/5/2018

Whales are Back!

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Photo obtained under N.M.F.S. permit #987

The first humpback whales of the season have been sighted in the waters off Maui!

by Deb Caswell, Whale Trust Board Member

Over the winter months, approximately 10,000 to 12,000 whales are expected to arrive in the Hawaiian Islands after a 4-6 week migration from their feeding grounds in the north Pacific. Humpback whales do not all arrive at the same time. Instead, their arrival is staggered and their length of stay depends on several factors including age and sex. Research has shown that adult males tend to stay the longest and females without calves the shortest. While humpbacks in Hawaii have been reported in every month of the year, they are rarely sighted before the beginning of the breeding/calving season in early fall (September/October). Their numbers reach a peak in mid-winter and taper off by late spring.

Most humpback whales summering in the northern waters of the Pacific Ocean head south to warmer sub-tropical waters during winter months. Breeding and birthing are thought to occur while in the warmer waters. Most of the these migrating humpbacks seem to come to the waters around the Hawaiian Islands (estimates of just over 50%). Since most were born in Hawaiian waters, they are coming “home” for the season. Their arrival is continuous over the winter months with peak populations occurring mid-January to mid-March. Certain groups seem to arrive at different times with young juveniles being the among the first. Overall, humpback whales have been sighted as early as late August and as late as July. It is estimated that males may stay in warmer waters about three months, a female who becomes pregnant may head north more quickly, and moms who calve may stay about six weeks, until their calf is strong enough to begin the journey north.

Over the past few years, our researchers have observed changes in migration patterns, with noticeably fewer whales and a breeding season that started later and ended earlier. Whales are an indicator of the health of the oceans. As such, it is imperative that scientists study these apparent changing trends. What might these changes be telling us?

At a Whale’s Pace

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With whales spending 90% of their time underwater, one of the biggest challenges for a whale behaviorist is to actually see them! Thanks to your generous support, we are now on the cusp of new discoveries into the underwater social lives of whales on the breeding grounds.

The warm, clear waters of Hawai’i make this one of the best places in the world to study whale behavior. It is one of the few places we can actually observe whales underwater, on the surface and from the air. Many research breakthroughs have come from of this unique natural observatory. However, since whales move faster than a person can swim, our understanding of their behavior is often based on pieced together, fleeting glimpses. Key questions remain – some as fundamental as when and where mating occurs.

To help answer these questions, this winter we will embark on a new project designed to bring together traditional research techniques (individual identification, sound recording and biopsy sampling) with new technologies (unmanned aerial vehicles and a mounted camera jib).

NEW TECHNOLOGY USHERS IN A NEW ERA OF WHALE RESEARCH

With the new accessibility of drones, unprecedented and high-quality aerial views of whale behaviors and interactions are now cost-effective and possible. Our new underwater camera jib, mounted under the boat, allows us to film whales moving at their natural speed. Together, these new tools promise to give us a new window into fast-moving social groups.

Instead of seeing whale behavior in brief moments, we can now capture longer sequences of whale behavior as well as interactions between individual whales. This is a tremendous leap forward—much like the first underwater photographs of whales in the 1970s and 80s, which significantly altered the world’s perception of these animals.

Our challenge is to compile as complete a picture as possible of the behavior patterns occurring in social groups on the breeding grounds. Capturing this in real time will provide a new key to understanding the nature of whales. It also will help set a new foundation of knowledge into humpback behavior for future management and conservation programs.

From the 2016 Whale Trust Maui Newsletter (November 2016). Click here to read more!

2017: A Critical Year for Humpbacks in Hawaii

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Next year (2017) may go down as one of the most critical years for humpback whale research in Hawaii in the last fifty years. For the first time since 1966 when whaling was deemed illegal in the North Pacific, humpbacks will no longer be considered an endangered species trying to come back from the brink of extinction. While there are many reasons to celebrate this recovery, on the heels of this landmark decision was one of the most abnormal winters on record for humpback whales across the Pacific Ocean.

The decision to delist humpbacks has left many researchers with mixed feelings on how to respond. On the one hand, there is no question that the number of humpbacks has increased substantially in most areas of the world since whaling stopped; and humpbacks will still be protected under the Marine Mammal Protection Act in the U.S. On the other hand, the decision does not reflect or indicate that we actually understand the biological, ecological, and social requirements for these populations to continue to recover and thrive in a changing world. Indeed, we are venturing into unchartered territory with no clear grasp on how the complex and changing landscape of their environment will impact populations going forward. All of which is vital to developing and implementing any kind of meaningful conservation and management program.

The winter of 2016, in terms of the sheer number of whales and the behavior of whales on breeding grounds across the North Pacific, was undeniably one of the strangest on record. There were noticeably fewer whales, changes in migration patterns (the breeding season started later and ended earlier), dramatic changes in behavior (less surface activity associated with mating strategies, longer downtimes), and fewer mothers and calves observed. In Hawaii, we speculated that far fewer females had shown up than usual. If indeed this is true, where were they? Did they not migrate as far south as usual? Did they stay on or around the feeding grounds? If so, how has will this affect reproduction going forward?

We have no idea what happened in 2016 or why. One aberrant season does not warrant a crisis. However, what it did emphasize was an almost shocking lack of knowledge about these animals, and the stark recognition of a large gap in current research efforts. Systematic monitoring on the abundance of whales on breeding grounds has become nearly obsolete over the past ten years. Without collecting this kind of consistent baseline data it is impossible to determine just how different from “normal” 2016 really was.

As such, Whale Trust is expanding our core research program to include a systematic monitoring component that will contribute to validating and investigating large-scale changes in abundance and behavior. Our commitment to research on social organization, behavior and communication has not changed – but if nothing else, 2016 told us we need to do more. The change in the endangered species designation of humpbacks makes this responsibility even more compelling.

So why is 2017 so important? It marks the first season of the official ‘recovery’ of the humpback population that ironically coincides with the biggest mystery on humpback status since whaling stopped. Consequently, monitoring breeding populations will be even more vital this coming season than in previous ones. Either the season will be similar to 2016 in which case some critical questions as to the health of the population will arise, or, it will be back to “normal” in which case we will be left wondering what happened – with lingering questions about how sensitive whales are to minor changes in water temperature and what this means in the context of global warming.

How to Identify Whales

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Humpback whales are easily identified based on the markings of the underside of the tail fluke. A photograph of these markings provides a permanent identification (ID) record of an individual whale.

Humpback Whale (Megaptera novaeangliae), tail, Humpback Whale NMS, Maui,Hawaii. Notice must accompany publication Photo obtained under N.M.F.S. Permit #753
Humpback Whale (Megaptera novaeangliae), tail, Humpback Whale NMS, Maui,Hawaii. Photo obtained under N.M.F.S. Permit #753

So How Do We Tell the Whales Apart?

A whale’s tail ranges from all black to all white to any combination in between. Researchers compare the overall color patterns, the scars, and the serrations along the trailing edge to differentiate one tail from another. 

Whale Tails are Important for Research

Identifying individuals is a crucial component of all wildlife research. From this data, we can learn vital information about individuals and populations, ranging from age, lifespan, reproductive histories, migration patterns, and population estimates to association patterns between individuals.

Over the years, Whale Trust Maui researchers have taken thousands of photographs of humpback whales that are organized into a photo-id catalogue and entered into a digital database.

Dr. Meagan Jones studying whale tails
Dr. Meagan Jones studying whale tails

Getting to Know Individual Whales

The Whale Trust Maui catalogue includes photos of individual humpback whale flukes that date back to the 1970s when Jim Darling was working on his Ph.D. We have information on some individual whales dating back to 1979. “Frank”, the first singer ever found and identified, has been seen multiple times since we first identified him in 1979. The most recent sighting was in 2011.