Photo by @BrianSkerry.
Happy #WorldWhaleDay Everyone!
A female adult sperm whale babysits a calf while the calf’s mother feeds in the deep waters of the eastern Caribbean. Sperm whales are the largest predators on Earth and have been portrayed as monsters throughout human history. Despite these misconceptions, researchers are shattering such beliefs and are revealing instead an amazing animal with sophisticated behaviors and even a sense of ‘family values.’ This ancient species was swimming in the sea before humans walked upright, and they possess the largest brains of any animal on the planet. Spending most of their lives in the deep ocean, we rarely see more than brief moments from the lives of these animals, and we’re forced to slowly piece together the puzzle of their lives. In the time ahead, more will be learned about their complex societies and cultures. Coverage from an upcoming @natgeo story.
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Silent Killers vs Chatterboxes: Differences in Transient and Resident Killer Whale Communication
There are two subspecies of killer whales that inhabit the eastern North Pacific: transient killer whales and resident killer whales. These two subspecies have not interbred for at least 250,000 years and display drastic differences in social structure, behavior, prey preference, morphology, and, interestingly, communication styles.
Transient killer whales feed exclusively on other marine mammals, such as seals, porpoises, sea lions, and even the occasional large whale. These marine mammals have excellent underwater hearing and are able to detect transient killer whale calls from several kilometers away and display anti-predator behavior when exposed to these calls. Therefore, “eavesdropping” by potential prey is an issue for transient killer whales, and it has shaped their vocal behavior. Transient killer whales are almost entirely silent as they go about their day. They only become vocal in two instances: after they have made a kill, and when they are participating in surface-active, social behaviors.
Resident killer whales, on the other hand, only feed on fish. Salmonids, their preferred prey species, have very poor hearing at the frequencies in which killer whales communicate. Therefore, resident killer whales are often loud, chatty, and can be generous in their use of echolocation calls.
There are three types of vocalizations used by killer whales: clicks, whistles, and pulsed calls. Clicks are used during echolocation and help whales orient themselves and locate prey. Whistles are used for socialization and in short-range communication. Pulsed calls are the most common form of killer whale vocalizations; they are used in group recognition and coordination of behavior. These calls are used by biologists to distinguish individual groups of whales.
During studies of resident and transient communication, researchers find that residents produce pulsed calls at a higher rate than transients. One study, published in 2005, showed that transients produce no vocalizations whatsoever apart from when they have made a kill or are participating in surface-active behaviors. What is the reasoning behind food-associated vocalizations? While we still are not sure, it is likely related to socialization. Transients frequently share prey amongst each other and high rates of vocalization after a kill may aid in doing so.
Photo: Eva Saulitis (left) and NOAA Fisheries (right)
Deeke V., Ford JKB., and Slater P. 2005. The vocal behaviour of mammal-eating killer whales:
communicating with costly calls. Animal Behavior, 69: 395-405.
Sea otters: cute and cuddly, yet surprisingly violent.
Sea otter mating behavior was on full display this afternoon in Seldovia’s harbor.
Male otters are aggressive when it comes to mating. He grips the female tightly with his arms and bites down hard on her nose, ensuring she can’t escape. It’s a bloody affair and females are usually left scarred; sometimes the wounds they receive can be fatal, and there is a very real risk of drowning.
This violent mating behavior may have an important function. Sea otters, like other mustelids, are induced ovulators and require vigorous copulation in order for the egg to be released.
a pod of eleven killer whales – a family of two adults and nine juveniles – was discovered trapped in the ice of the hudson bay off the coast of the small inuit village of inukjuak. confined for two days in the small breathing hole, the whales began to panic as they tried unsuccessfully to find another breathing hole and their way to sea.
while an icebreaker ship would typically be brought in to free the orcas, the closest crew was thirty six hours away, so the villagers decided to cut a half mile of holes for the killer whales to travel through on their way to open water. the village mayor noted that it was unusual to see orcas in the area in january, but that the waters were late to freeze that year. (photos)
“Baby humpbacks take these short dives to nurse while their mom lays relatively still at the surface. I’m not too sure how many gallons of milk they consume but based on how fast they grow it must be a lot! A future project I want to work on is using the drone to measure the growth/loss rate for mom and calf!”
Resident Killer Whales: The Ocean’s Most Dedicated Mother
On Mother’s Day, many of us take the time to honor our mothers and all of the time, energy, effort, and love that has gone into raising their children.
For resident killer whales, an unnamed subspecies of killer whale found only in the North Pacific, motherly love transcends all other boundaries found in the animal kingdom. In resident killer whale society, a female’s offspring never leave her side.
This phenomenon, known as natal philopatry, is seen in many species, but killer whales take it to a whole new level. Both female AND male offspring stay with their mother for their entire lives. Natal philopatry of both sexes is very rare in mammals, being seen only in two bat species, pilot whales, and of course, resident killer whales. 
Male resident killer whales in particular are true “mama’s boys.’ While mature female killer whales will retain some degree of independence from their mothers, males are extremely dependent on their mothers. In fact, a male resident killer whale is 3.1 times more likely to die in the year following the death of his mother. For males over the age of 30, the risk of death increases over 8 times after the death of their mothers. This may be because older mothers often provision their adult male offspring. Without mom around to help feed him, a male may have more difficulty surviving. For males, having mom around also means they have higher reproductive success.  
Alaskan resident male AP10 and his probable mother, AP2.
Killer whale moms are so important that they are one of only a few species to display reproductive senescence, also known as menopause. In most animal species, a female continues to reproduce for her entire life. In killer whales, females generally stop reproducing around 40 years of age, but can easily live 30-40 years more after reproduction ceases. One main hypothesis that explains this curious aspect of killer whale biology is that elderly female killer whales are repositories of information that aid in group survival. These “grandma” killer whales are the leaders of pod movement during foraging, and their leadership is especially important in years when salmon––resident killer whales’ main prey source––is low. 
Moms are important to us all, but for killer whales, a mother is the ultimate key to survival. Without such dedicated mothers, killer whale society as we know it would likely be radically different.
Happy Mother’s Day to all mothers out there, especially the ones of the flippered variety.
For further reading, please refer to the sources under the cut.
Although humpback whales are large, they only feed on krill and small fish. Photographer Douglas Croft snapped this photo of a humpback whale taking a big gulp of anchovies! Humpback whales and other whales flock to the nutrient-rich waters of Monterey Bay National Marine Sanctuary to feed. By winter, most humpback whales leave the sanctuary for warmer waters in Mexico, but some juveniles and non-breeding adults stick around a little longer to take advantage of the over-whale-mingly large feast.
Everything we thought we knew about killer whales has been shaken up.
Today, the article “Infanticide in a mammal-eating killer whale population” by Towers et al. was published in the journal Nature. It documents the very first case of infanticide (the killing of an infant) in killer whales. It is also the first case of a mother-assisted infanticide in a species other than humans.
Up until now, aggressive interactions between killer whales (in the wild, at least) were virtually unheard of. Just the other day I was pondering the lack of violence in killer whale society. But just as killer whales tend to do, they upturned everything we thought we knew about them.
The attack involved the T068s and T046Bs, two families of West Coast Transient killer whales.
Post-reproductive female T068 and her son, T068A, attacked mother T046B and her offspring. A previously undocumented neonate, dubbed T046B5, was present, and it became clear that this calf was the target of the attack.
Figure caption from the article: “Observations leading to infanticide. (A) Fresh wounds on left flank and kinked spine anterior to dorsal fin on T046B4. (B) T046B with offspring T046B2 and (neonate) T046B5. (C) T068A surrounded by T046B, T046B1 and T046B1A. (D) T046B ramming T068A from below sending spray and blood into the air.”
T046B attempted to protect her calf by ramming the male T068A. Other members of the T046B family also appeared to try and get the calf back. At one point, T068A had grabbed the neonate by the flukes and likely had drowned it. He paraded the calf’s carcass around in his mouth. Both he and his mother took turns carrying the calf around while the T046Bs trailed behind them. The researchers recording this attack were also using a hydrophone to listen to the whales’ calls, and they documented highly erratic vocalizations that have never been heard before.
Figure caption from the article: “Observations following infanticide. (A) T068A with the fluke of T046B5 in the left side of his mouth. Fresh scars from the teeth of another whale can be seen on his left flank and rostrum. (B) T068 surfacing with the fluke of T046B5 visible in the left side of her mouth. (C) T068A surfacing with the dorsal fin of T046B5 visible off the left side of his melon. (D) T068 rostrum to rostrum with T046B5 approximately 215 minutes after its death.”
Eventually, the light was dim and researchers had to leave the group.
This leaves us all wondering: what is going on? Why did the T068s kill a neonate calf? In other species, infanticide is fairly common as the killing of an infant often brings the mother back into estrus and males can mate with her. It’s likely this is what was going on as other explanations, such as competition for resources, do not adequately explain it.
This is a major discovery in killer whale behavior and I have no doubt we’ll learn more as the years go by.