by Rob Nawojchik
The gray whale is perhaps the species of whale that inspires the most people to take our 12-day Natural History Tour to Baja California, Mexico. There are many fascinating aspects of the gray whale’s story, from biology and behavior to the history of human exploitation. Gray whales are the most coastal of all the large whales and can often be seen from shore during their annual migration between Alaska and Baja. Hunted to near-extinction, the eastern North Pacific gray whale population has recovered to healthy numbers, the epitome of a conservation success story. During their winter/spring reproductive season, gray whales congregate in shallow-water lagoons along the west coast of Baja California. Because of the high concentration of gray whales in the relatively confined areas of the lagoons, the whale-watching opportunities are unparalleled. Perhaps the most astonishing thing is the gray whales’ penchant for “friendly” behavior, in which they approach and get very close to exuberant whale watchers (who are floating in the lagoon in small skiffs or “pangas”), sometimes initiating physical contact with the astounded eco-tourists.
Much can be (and has been) written about the ecology and behavior of the gray whale. Today’s focus, however, is on identification (ID). If you are lucky enough to be at one of the gray whale lagoons between January and April, then the large whales you are seeing are gray whales. The other large whale species of the region do not enter the lagoons. (Note: San Ignacio Lagoon, the lagoon the Searcher visits each year, is alive with all sorts of marine life: bottlenose dolphins, a few California sea lions, sea turtles, and lots of seabirds, but no whales other than gray whales.) In addition to the lagoons, we see gray whales in the ocean along the Pacific coast of the Baja peninsula (and every once in a while in the Gulf of California / Sea of Cortez). The following ID characters will help you identify gray whales, whether it’s from a distance in their oceanic migratory corridor, or up close and personal from inches away in the lagoon. One last side-note before we begin: in past blogs I warned how whale sightings are often from miles away and how difficult it is to get a good view of the animal. You will NOT have that problem in the lagoon! Your biggest problem in the lagoon will be keeping your glasses and camera lens clean after repeatedly getting drenched by the whales spouting next to the panga.
Size and shape of spout/blow: Like most of the large whales in the Baja region, the gray whale produces a visible blow that can be seen from quite a distance under good conditions. However, the height of the blow is perhaps only a third to a half of the height of a blue whale blow (which makes sense; the height of the blow is partly a function of the size of the animal). In terms of shape, the gray whale blow might be described as “bushy” when viewed from the side, but can appear to be heart-shaped or V-shaped when viewed from in front of or behind the animal. In the Baja region, the gray whale is the species most likely to produce a heart-shaped blow. From a distance, the bushy blows of gray and humpback whales can appear similar, especially under windy conditions or if your view of the blow is at the wrong angle. As always, when identifying whales at sea, multiple clues are usually needed before a confident ID can be made.
Size of animal: I like to organize the six species of baleen whales commonly seen in Baja into three size categories: big (blue and fin whales), medium (humpback, Bryde’s, and gray whales), and small (minke whale). Most of the adult gray whales we see are probably between 36 and 50 feet (11-15m) in length (roughly similar to the humpback and Bryde’s). Of course, we also see lots of calves at San Ignacio Lagoon. Gray whales are about 15 feet (4.5m) at birth, but grow rapidly while nursing in the lagoon.
Color: The color of gray whales can best be described as blotchy gray and is very distinctive compared to other whales, thus serving as a useful species-identification character. The color pattern is highly variable between gray whales, providing a feature useful for photo-ID catalogs of individuals. Photo-ID is a very important tool used by marine mammalogists to answer all sorts of ecological and behavioral questions.
Dorsal fin: The gray whale does not have a dorsal fin, which will distinguish it from all the other baleen whale species in the region. Instead, there is a slight dorsal hump where the fin would normally be, followed by a series of bumps (often referred to as “knuckles”) along the dorsal ridge between the dorsal hump and the tail.
Tail flukes: The gray whale is among those species that sometimes show their flukes when diving. As with the body, the color of the flukes on both surfaces (dorsal and ventral) is blotchy gray. The trailing edge is generally smooth. We sometimes see “rake marks” on the tail flukes, pectoral flippers, or elsewhere on the body. These patterns are scars left by the teeth of killer whales, a testament to failed attacks.
Species-specific traits: Already-mentioned diagnostic characters include the lack of a dorsal fin and the particular color pattern of gray whales. Another very useful identification feature is the encrustation of ectoparasites, in particular barnacles and “whale lice”, on the skin of gray whales. Most, if not all, species of whales have external parasites of various types. In the case of gray whales, the parasites are quite obvious and can cover a significant portion of the skin, especially around the head. The species of barnacle found on gray whales is host-specific; in other words, it is found only on gray whales. The “lice” are really a type of crustacean called a cyamid; four species of cyamids can be found on gray whales. Gray whale calves are born without any ectoparasites, but soon start acquiring them even while nursing in the lagoons. During our visits to San Ignacio Lagoon, we can get a rough idea of the age of a calf by the number of barnacles and cyamids encrusting the skin. (Note: although I’ve referred to cyamids as parasites, they may be harmless to the whale or even beneficial in some ways.)
Behavior: I’ve already mentioned the fluking behavior of gray whales (other flukers include the blue, humpback, and sperm whales). I’ve also remarked on the gray whales’ use of lagoons for breeding and calving. Among large species of whales, this use of lagoons is unique to gray whales. Two additional behaviors of gray whales worth noting, both commonly seen in the lagoons, are spyhopping and breaching. Spyhopping is when a whale lifts its head out of the water, ostensibly to take a look around. Although humpback whales are known to spyhop, we do not normally see spyhopping behavior with humpbacks in the Baja region. Breaching is when a whale jumps from the water, either partly or entirely, and then re-enters with a huge splash. A breach might be the most dramatic behavior in a whale’s repertoire. Many species of whales have been known to breach, but in the Baja region the two species that breach most often are the gray whale and humpback whale.