The Marine Mammal Protection Act (MMPA) was enacted in 1972.

A wide variety of plants and animals live in the ocean, including a number of mammalian species who, like humans, are warm blooded, bear live offspring and nurse their young. There are many different types of marine mammals, including whales and dolphins, manatees, seals and sea lions, polar bears, otters and more. A number of these species have been threatened in the past by various human activities, including hunting, fishing and boating. Whale populations, in particular, have been severely depleted by hunting over the last two centuries. In 1972, Congress passed a law recognizing the dangers posed to marine mammals by human activities, mandating that these dangers should be reduced, recognizing the value of protecting these mammals and directing that measures be taken to restore the health and viability of endangered populations.

Xpeditions
In The Best Hope for Northern Right Whales (9–12), students research current and proposed methods of assisting the recovery of northern right whale populations. Students conduct Internet research to investigate the best strategies to help save right whales. An extension activity has students do data graphing to analyze whale populations.  

What Are Manatees? (K–2) introduces students to manatees. Students learn about manatees' behavioral characteristics and how manatees in captivity interact with people. They conclude by creating "manatee booklets" to educate others about this species.

In Right Whales and People (K–2), students learn about the highly endangered northern right whale and think about how this species' geographical distribution places it in direct contact with human threats such as ships. Students draw pictures of right whales and add commercial ships and other human activities to their drawings. They conclude by writing sentences explaining how the whales they have drawn might be affected by human activities and what might be done to help the whales.

In the activity Build a Whale of a Crittercam (K–12), students help the Crittercam team study humpback whales.

Science NetLinks
The Science Update Deaf Manatees (4–12) attempts to shed light on the problem of the injury of manatees through collisions with powerboats in the Florida Everglades. Students learn about the results of tests performed by researcher Edmund Gerstein, who discovered that manatees are in fact deaf, rather than dumb, as had been previously theorized.

The Science Update Bouncy Blubber (6–12) focuses on the form and functions of marine mammals' blubber. Through reading and research, students discover that blubber is a good deal more complex and serves many more purposes than scientists once believed. Using a 90-second net-radio format, Science Updates are mini-lessons designed to introduce and investigate various scientific concepts.

Dolphins' and other marine mammals' brains are quite large compared to the size of their bodies. Scientists say that the brain size of dolphins is an indication of high intelligence. In the Science Update Dolphin Brains (3–12), science reporter Bob Hirshon introduces students to one scientist whose work is in trying to find out more about dolphins and their brains.