The scientific name for seals, sea lions, and walruses is Pinnipedia. Its Latin root means "fin-footed" and refers to the modification of limbs to flippers. Pinnipeds have four flippers – one pair in front and one pair in back.
Pinnipeds share five common characteristics with other mammals: they’re warm-blooded, give birth, nurse their young, breathe air, and have hair. Since they live in the marine environment and they find their food at sea, pinnipeds are called marine mammals. Other marine mammals include whales and sea otters.
Although they spend most of their lives in the water, pinnipeds, unlike whales and dolphins, are also dependent upon land. Pinnipeds may come ashore periodically to rest and bask in the sun, and at least once a year, during their breeding season, most species congregate on beaches to give birth and to breed.
Seals are smaller and have a sleeker, torpedo type of shape. They move with a rhythmic sliding or shuffling motion, and they don’t use their flippers to support their body. Harbor seals are very shy and rarely bark.
Sea lions are larger, with longer flippers and are very vocal. They can support themselves on their two front flippers and actually walk. They are more territorial and aggressive than seals. Give sea lions a wide berth.
These animals need to come ashore for many reasons. Most of the time, they rest on jetties or other objects out to sea, like large buoys or large rocks. When the surf is large and stormy, they might come to shore to rest or to get warm. At times, they come to shore if they are sick or lost.
Nothing! Please don’t approach these animals. They can be very territorial and they bite! If you see one on the beach, please call the lifeguard service closest to your city. You should remain a safe distance from them at all times, and leave them alone. Keep in mind they have very sharp teeth and may bite if cornered or harassed.
The Marine Mammal Protection Act makes it a violation of Federal Law to interfere in any way with the natural behavior of the marine mammals. If your actions cause the animals to alter their behavior, you may be found in violation of this law. To report violations, advise the on-duty lifeguard service or call the National Marine Fisheries at (619) 557-5994 or (310) 980-4049.
Over 200 different species of jellyfish are found throughout the world’s oceans and seas. Although they don’t often appear in Oceanside, we want to share a little bit about them. They are also known as invertebrates, animals lacking backbones. They belong to the phylum Cnidaria (ny-DARE-ee-uh). They come in many shapes and sizes, ranging from the thimble, to the spherical jellyfish of the Caribbean, to the largest jellyfish of them all, Arctic lion’s mane, whose tentacles may stretch over 100 feet in length.
Jellyfish are over 95 percent water and have no heart, blood, or gills. Despite limited sense organs, jellyfish can smell, taste, and remain balanced in the water. Jellyfish also have light-sensing organs around the bell rim, and although jellyfish cannot detect objects, they can distinguish light from dark. Jellyfish can sense smell and tastes using chemoreceptors. Touch receptors on the tentacles, oral arms, and around the mouth sense movement and help jellyfish find food. In addition to swimming, jellyfish are carried by wind, waves, and currents. They swim using jet propulsion. Special muscles called coronal muscles, embedded on the underside of the bell, push water out of the hollow bell. As water is pushed in one direction, the jellyfish moves in the opposite direction. Jellyfish are most known for, and avoided for, stinging cells located on the tentacles and other body parts. The stinging cell consists of a capsule with a sensory hair, a lid and an interior nematocyst, (nee-MAT-o-sist) which actually stings, captures and subdues prey.
Even a jellyfish that has washed ashore should not be handled, since moist nematocysts may still fire. The stings of some jellyfish may be quite painful, causing mild rashes. Although feared by swimmers, most jellyfish are harmless to human beings. In fact, these graceful creatures can benefit people and should be appreciated. Several different kinds of jellyfish are being used to treat certain cancers and heart diseases.