The polar bear is more than just a big mammal; it’s an icon for an entire region -- it’s hard to think of the Arctic without picturing these beautiful creatures. Yet it’s also a symbol for how that region is changing. A warmer climate is reducing the amount of sea ice in the Arctic, which could lead to a big reduction in polar bear populations.
No bear is bigger than the polar bear -- an adult male can weigh up to three-quarters of a ton. To maintain that size, polar bears spend much of their time hunting seals, which are rich in fat and calories.
You may have heard that starfish can regrow arms they’ve lost, but imagine a creature that can regrow nearly all its internal organs. Sea cucumbers have no brain, eyes or heart, but when they have to protect themselves, they turn themselves inside out and eject their intestines, reproductive organs and respiratory tissues. But these soft tube-shaped animals can regrow all that tissue within about six weeks. Researchers hope studying the sea cucumber’s remarkable regeneration abilities will offer insights for human medicine.
