America's Animals

Offshore

America's domain does not stop with its shorelines, and more of America's animals may be found below the waves of our coastal waters. Below are three of them.

Blacktip Shark

The blacktip shark (not the same as the blacktip reef shark) is found in tropical and subtropical waters, such as the Gulf of Mexico. It is not an open-water shark, preferring to stick to coastal shelves, and usually found in 100 feet or less of water. Blacktip sharks typically grow to about 5 feet long, although larger ones have been found. They feed on a wide variety of fish, and are fast in pursuit of their prey. Females give birth to live young, 10 or less at a time, every other year. Although some attacks on humans have been recorded, most have caused only minor injuries. Humans are much more dangerous to this shark than vice versa -- the population is currently listed as "Near Threatened" by the International Union for Conservation of Nature, because the species' low reproduction rate makes it vulnerable to human overfishing.

Bottlenose Dolphin

The Bottlenose dolphin is the best-known species of dolphin, recognizable to many people from the TV show "Flipper," and frequently seen in oceanariums and along coastal shores. These graceful and powerful creatures generally reach about 8 feet in length, although there is considerable variation in size, largely depending on where they live. They have good eyesight, but also use "echolocation" to help them hunt and gather information about their surroundings. Echolocation is the use of focused pulses of sound by the dolphins -- they listen for and interpret the echoes when the sound pulses strike an object and reflect. Bottlenose dolphins are extremely intelligent -- they are known to use tools, possess culture, and to be self-aware.

Moon Jellyfish

Moon jellyfish are very widely distributed, with several closely-related species. They are found in more than one ocean. They prefer warmer, coastal waters, but can tolerate much colder water. They are relatively small, being about 16 inches or less across the central portion, called the bell. Moon jellyfish have some ability to swim, but largely drift with the currents. The tentacles are lined with stinging cells called nematocysts. Their prey is a variety of very tiny creatures called zooplankton. The 4 bright U-shaped things seen in the middle of this moon jellyfish are its reproductive equipment. Moon jellyfish are eaten by a number of other creatures, including leatherback sea turtles, ocean sunfish, and some other types of jellyfish.