Copyright 1994 Oceanic Research Group, Inc.
All Rights Reserved
Dawn. A small herd of harbor seals is resting an isolated rock, hardly large enough to be referred to as an island, over twenty miles from the mainland. This is where many species of seals are usually found: isolated areas away from people and commotion. These harbor seals are enjoying a very important facet of their lives: their resting time spent on dry land between bouts of swimming in cold water in pursuit of food. Join us, as we journey to the waters of New England, in search of the elusive and isolated seals making their homes in this remote region.
The search for seals is not an easy one, and even we did not realize the difficulty of the task facing us when embarking upon this mission. Seals prefer to live in isolation, far from human populations. Hundreds of years of hunting by man has taught the seals to be wary. When the U.S. marine mammal protection act was passed in 1972, seals were nearly gone from most of New England.
Our journey begins in Maine, aboard a chartered boat steaming towards an uninhabited island in the chilly North Atlantic Ocean. Although the occasional seal can be seen swimming by in a harbor, only remote islands will contain colonies of seals hauled out on the rocks.
We're dropped off on the island for what we think is going to be several days of filming, but soon discover that there are no seals! Of course, we find things to do while waiting for the boat to return. Eventually, we hitch a ride out on a barge!
Finally, we locate an island with seals on it, but then face the task of sneaking up on them to begin filming. This is easier said than done. The eyesight of seals is keen in the water, but somewhat limited on land. However, their hearing and smell are excellent, both in and out of the water. This makes a stealthy approach necessary. Even when we take great care to approach the seals undetected, sometimes they still sense us, and quickly slip off the rocks into the water, for safety. Although seals are awkward on land, they are swift and graceful in the water, and they will always seek the water for protection.
We find two species of seals here in New England, the common Harbor seal, and the comparatively rare Grey Seal. While both Harbor seals and Grey Seals were hunted extensively in the past, the Grey seal population was pushed to particularly low levels.
Both Harbor seals and Grey seals are contained within the Family of so-called "True" seals. True seals have short front flippers which are not long enough to enable the seals to lift their bodies off of the ground while on land. This makes true seals somewhat handicapped on land, and they must get around with an awkward crawl. In the water, however, they swim gracefully, using their front flippers for steering and their hind limbs for propulsion.
Although the true seals do have fur, they are not to be confused with the family of seals known as Fur Seals. Fur seals have long, muscular front flippers, used to hold the body up and walk when out of the water. These muscular front flippers also provide the swimming power. Surprisingly, Fur seals (like this Sea Lion) are not found in the entire Atlantic Ocean.
All seals are marine mammals, which means that they breathe air and bear live young, just like all other mammals. It is believed that they evolved some 30 million years ago from land mammals.
The evolutionary relationship to land mammals is perhaps most obvious in the flippers, which still retain the finger bones of distant ancestors, even though the fingers themselves have long since been lost in order to form the flipper.
Although the fingers may have been lost, the nails have not. Both Grey and Harbor Seals still have nails on their flippers, helping them find traction when struggling onto land from the water.
The ears of these seals consist of small openings located behind the eyes, having no external ear-lobes. These ear openings, like the seal nostrils, can be tightly closed while diving, in order to keep water out.
Several hours per day are spent foraging for food. Seals will hunt many species of small fish, including flounder, alewife, herring, harbor pollack and many others. But they also enjoy squid, when they can find them.
During periods of rest, seals haul themselves out of the water and relax on the rocks, using the sun's energy to warm up. Choice rocks are always in demand, and sometimes arguments take place over who gets what spot. These arguments are usually short-lived, and the seals soon return to snoozing and relaxing. A scratch always feels nice too.
Harbor seal mating occurs in the water during the summer months. The males (called bulls) will attempt to mate with as many cows as they can. The pups are born almost a year later in the late spring. Each cow usually produces only one pup, which she nurses for only about a month. The cow recognizes her pup both by smell and by call. When the cow is done nursing, she leaves her pup, and goes off to mate again.
The pup is then left to fend for itself. It searches for food which is easy to catch, such as invertebrates. When it becomes a faster swimmer and a more skilled hunter, it will move up to fish. This pup, which is a little under 3 feet long, is about 3 months old, and is fully weaned from its mother. It has found a nice cozy tide-pool in which to nap. The water in the tidepool keeps the pup from overheating in the harsh July sun. Harbor Seals vary in color between brown, tan and grey. They live to be about 35 years of age, perhaps more. It will take between four and six years for a harbor seal to be fully grown, at which time it may reach over five feet in length and 250 pounds.
Mature Grey Seals grow much larger than Harbor Seals, reaching 8 feet and 800 pounds. Like all seals, when Grey Seals dive, they slow their heart rate to conserve oxygen, a process known as bradycardia. The amount of bradycardia a Grey seal employs is a function of dive duration. One study found a Grey Seal which slowed its heart rate from 115 beats per minute at the surface to only 2 beats per minute while engaged in a long dive! Studies have also shown that Grey seals prefer to travel underwater, because it is more efficient for them than swimming at the surface. Grey seals can remain submerged for over 25 minutes if necessary, and can easily dive to depths of 300 feet.
To film the underwater activities of the seals, we dive every day for weeks on end. For most of the dives during our filming, the seals keep their distance, never approaching us very closely. We always enter the water hoping for the best, but end up spending much of our time merely waiting for the seals to swim by. An underwater encounter with marine mammals has to be done on their terms, because they are so fast and well aware of their surroundings. It is simply impossible for divers to keep up with them. Seals can even swim circles around sharks. Therefore, we have to earn their trust in order to get close enough to film.
Eventually, perseverance pays off, and we do earn their trust. Curiosity gets the best of a seal or two. They swim by for a glance at us, never lingering more than a few seconds.
As time goes on, the younger Grey seals can't stand the temptation, and come over to give us a thorough investigation....of course, they wait until we're not looking and sneak up behind us! Usually only one at a time, the animals then begin to regularly approach. We stay completely still, to avoid frightening them.
After a while, these daredevils come right up to us, apparently determined to figure out just exactly what we are. They are interested in examining any brightly colored or strangely shaped objects, first and foremost being our dive fins. The whiskers on the seal's face are used as sensory organs, to detect vibrations in the water and to help investigate objects.
At one point, the seals begin to taste our drysuits, and for the first time, we get a glance at their razor sharp teeth used for catching those slippery fish! The purpose of this suit tasting is unknown, but it is a harmless form of investigation to which we do not object. Even with their sharp teeth, quite capable of inflicting injury, they are very gentle with us. They take an interest in our cameras and lenses. It seems as if they are methodically checking out every piece of gear we have brought. Even our hoses and gauges are inspected. The moments we spend with the seals are truly remarkable. Remember: these are wild animals....just as wild as wolves, or tigers. That they will approach us at all is a real credit to their curiosity. But when they get bored, they simply swim away and we lose sight of them rapidly in the cloudy North Atlantic Ocean.
These animals, appearing clumsy and sluggish on land, become swift and graceful when seen in their true element. Fortunately, the story of the New England seals has a happy ending, as they are recovering well from the years of human abuse which they have suffered. Protection of the seal is working. Seal populations are healthy, and growing. With any luck, someday the New England seals will be as numerous as they once were. Anyone who has ever met one of these curious and obviously intelligent creatures will probably admit to having developed quite an affinity for them. Seals are a symbol of the natural beauty of the diversity of life in the oceans. We can't undo what we have done to seals in the past, but its over, and with luck, time will heal the wounds. To understand the seals is the most important step. To allow them to live their lives, wild and free, is the best thing we can do for them. Perhaps someday, then, the oceans will again be teeming with these fascinating marine mammals, which remind us so much of playful, undersea puppy dogs.