Answers From the Gray Whale Expert
Spring 2013
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Q:  How smart are gray whales compared to other whales? Dolphins?

A: This is a very good question, and difficult to answer. Many people use the word “smart” or “intelligent” to compare various animals with people. Some hallmarks of “intelligence” are: being self-aware, being able to solve complex problems, being able to communicate on a sophisticated level, and having culture (learned traditions passed on through generations). Using these measures, bottlenose dolphin and orcas (very social, toothed whales) are considered to be VERY “smart”; both have been extensively studied in the wild and in captivity. In contrast, gray whales are not very social; they do not live in family units, and do not need to cooperate to find food. With the exception of two calves (Gigi and JJ), gray whales have not been studied in captivity. Based on what is known so far, gray whales are not considered to be as “smart” and dolphins and orcas. 

Q:  How will warmer water temps affect gray whales?

A: Gray whales are highly adaptable. Because they migrate to warm water nursery lagoons in the winter, and then to cold water Arctic feeding grounds in the summer, they are able to tolerate wide ranges in both water and air temperature. However, warmer Arctic feeding ground temperatures can reduce the abundance and distribution of their prey: they may not be able to find as much of their preferred food in their usual feeding areas. They may have to range further to find more food in other areas, and may take longer to find enough food; this may cause them to migrate later. Although gray whales prefer to eat amphipods (shrimp-like organisms that live in tube dwellings on the mud), the very good news is that gray whales are known to eat at least 85 different prey species! They are VERY flexible in their feeding habits. Gray whales are actually known as an “ecosystem sentinels” because they visibly respond to environmental changes.

Q:  How can such a huge animal float?

A: Gray whales have a fairly thick layer of blubber (fat), averaging 6 inches deep. Fat is lighter than water; this helps the gray whale float (gives it positive buoyancy). Gray whale calves, however, are born with very little blubber; they have to struggle a bit to stay afloat. The warm water of the Baja nursery lagoon helps a calf conserve heat; this water easily evaporates, and the salty dense water helps the baby float. The milk they drink from their moms is very high in fat (53% butterfat), allowing them to quickly transfer that milk into baby blubber as they grow. Bowhead whales live only in cold Arctic waters; adult bowheads can have a blubber layer that is over 2 feet thick! 

Q:  How long does the baby whale stay with its mom after they get back to the Arctic?

A: The calf usually nurses for about seven months, and stays with mom up to 9 months (until around August or September). So they stay with their moms until the feeding season is nearly over — or perhaps a bit later.

Q: In March, when someone reported seeing moms and babies by California already, could they mean whales that are a year old but still small so they'd look like a baby?

A: No. These babies are calves that were born earlier this season— not yearlings (born last year). For example, observers at our ACS/LA Gray Whale Census and Behavior Project saw our first northbound mom and calf on March 22. We often see our first pairs in March, although the majority of our cow/calf pairs pass by Pt. Vicente, CA in late April or early May. Most gray whales give birth in a 6 week window period, between the last week of December and the first week of February. The early cow/calf pairs are likely ones that include older calves (born in December), who have had a chance to pack on blubber and practice swimming skills in Baja CA!

Q: Do these whales live in families like they said in the movie Big Miracle?

A: No. Although “Big Miracle” was based on a real story of rescued gray whales, some facts were changed in the making of this movie. The movie depicted a family unit: a father whale, a mother whale, and their baby. However, gray whales do not live in family units; the only stable unit is the mother and calf, and that bond lasts for less than a year. In the ACTUAL rescue, the three gray whales included two adults and a juvenile (relationships unknown). NOTE: No one can tell whether a gray whale is a boy or girl by looking at their heads sticking up in the air as they spyhop (like they did in the movie). You need to see their undersides to tell if they are boys or girls. 

Q: Why do killer whales go after such big animals as gray whales?

A: Baby gray whales are a huge source of nutrition for killer whales; this can be shared among many family members. Killer whales eat the equivalent of at least one seal or sea lion per day; one gray whale can feed several families of killer whales for over a day! 

Q: What could happen to gray whales if there's no more ice in the Arctic? Would migration still happen?

A: Gray whales do not migrate because of the ice in the Arctic. They migrate north to access abundant prey resources. They migrate south for the warm water nursery lagoons that help provide sanctuary (from killer whales and bad storm waves) for their calves. If there was no more ice in the Arctic, the shortened day lengths would likely continue to be their primary migration cue; they would still migrate, but their migration TIMING would likely change.  Today’s southbound migration starts over a week later than it did 33 years ago (1980); many more calves are now born during the southbound migration as a result of this delay. Retreating seas ice would likely result in gray whales delaying their southbound migration even more. On the NEGATIVE side, this would mean that even MORE calves would be born during the southbound migration; the further north these calves are born, the longer the distance they will have to travel to Baja - and many would certainly not survive. On the POSITIVE side, this delayed timing would allow the gray whales to forage longer in newly opened feeding areas, adding to their blubber storage layers—which would improve their nutritional conditions and likely increase their chances for sustaining pregnancies (increased birth rates). As ice retreats and the Northwest Passage opens up and remains open longer, gray whales may move through this passage and re-colonize the Atlantic Ocean: one gray whale has apparently made this crossing already—appearing first near Israel and then near Spain in 2010!  

Q: I would like to know what you as a scientist still wonder the most about gray whales.

A: I have three big questions regarding gray whales:

1. What percentage of gray whale calves is killed by orcas each year? We know that many gray whales bear scars that show that they survived these attacks. Since I am both a gray whale and killer whale researcher, this question really interests me.

2. If our eastern Pacific gray whales and the very rare western Pacific gray whales (fewer than 130 whales) do not interbreed, how can they share part of the same migration path yet still recognize other “Russian” gray whales and know to breed only with them? Several of these whales were tagged over the past few years; all of the longest lasting tags showed that these whales actually crossed the Pacific Ocean and headed south toward Baja nursery lagoons, rather than stay in the western Pacific and head south to other nurseries. Genetic studies suggest that these whales do not interbreed with our gray whales, although they apparently share part of their migration route. They are likely different species!

3. How long can gray whales live? Reportedly it is at least 50-70 years. Hopefully we will have this answer in…another 50 years or so!

Q: Why breach?

A: In most cases, there is no way that we can know exactly why one specific whale is breaching at a particular time. Breaching can certainly be used as a method for stunning prey; this is often seen in orcas that feed on marine mammals, and occasionally in humpback whales that are feeding on schooling fish. Other hypotheses: to communicate (“here I am!”), power demonstration, or playfulness and muscle development for young whales. Because gray whales have so much whale lice (three different species) that are undoubtedly very itchy, they might sometimes breach to help dislodge some of those pesky little creatures; some gray whales do stop along migration to rub on sandy substrates, such as off of Zuma Beach, CA - most likely to help get rid of their parasites. If a whale becomes entangled in fishing gear, it might try to breach to free itself; I have observed this in gray whales a few times. After becoming disentangled, humpback whales have been known to breach multiple times: no doubt testing their bodies and feeling overwhelming relief!

Q: How deep can gray whales dive? Do they travel at great depths when not feeding? Why or why not?

A:Gray whales primarily migrate relatively close to shore; they feed in very shallow water. Since they do not need to dive deep for food, and since most migrate in shallow waters, there is no need for them to dive very deep. When on migration, they often follow relatively shallow contour lines (water depths); they likely choose migration routes based more on water depth than on distance from shore. They are able to dive down to depths of at least 500 feet. In contrast, sperm whales feed on squid that live in very deep water; they are adapted to dive to at least 10,000 feet deep in order to forage for their meals!   

Q: What are the pectoral fins called?

A: Pectoral flippers (“pecs”). 

Q: What is the significance of lying on its slide and slapping its pec fin...and what's that action called?

A: This behavior is called flipper slapping, or pec slapping. Humpback whales and killer whales do this behavior much more often than gray whales. This behavior can be a form of communication, since sound travels 5 times faster under water than in the air. It can be a show of power. In killer whales, it is sometimes used to stun prey such as seals, sea lions and birds.

Q: Approximately how fast do they swim on their northward migration as compared to the southward one?

A: Gray whales typically swim at speeds of 3-6 miles per hour while on migration. They swim somewhat slower on their northbound migration than on their southbound migration. On the southbound migration, pregnant females are hustling to get as close as they can to the warm water Baja lagoons before giving birth. On the northbound migration, those same females swim more slowly and often pause to nurse and rest. We also tend to see more milling and socializing behavior on their northbound migration.  

Q:  How big are the pods usually on the northward migration? It seems like the moms with calves are in the middle of a pod of five or six. Are these escorts females and males?

A: Most northbound gray whales travel in pods of two whales. Most southbound grays are seen as singles—although on January 20, 2013, I saw a pod of at least 23 southbound gray whales! We sometimes see larger pods; very occasionally we see pod sizes of over 10 gray whales.
The moms with calves rarely travel in large pods; cow/calf pairs are usually solitary, but sometimes join together during periods of peak migration. No “escorts” accompany gray whale cow/calf pairs; however, a male escort commonly accompanies a humpback whale cow/calf pair.

Q: Do last year's calves accompany these new calves, or do they travel separately?

A: There is absolutely no evidence demonstrating that yearlings (last year’s calves) accompany the new calves. Nearly all cow/calf pairs travel by themselves. During peak cow/calf migration periods, pairs may join up and travel together. Occasionally another adult may join them; we just saw this combination on April 21, 2013! VERY rarely a juvenile accompanies a cow/calf pair; we have no way of knowing if that juvenile was the calf’s older sibling.

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