Sure, scientists in Dallas may have come up with an invisibility cloak, but octopuses and squid beat them to the punch. Masters of disguise, among the tricks up their tentacle sleeves is this one: They manipulate sacs of black pigment on their skin to either shroud them in darkness to match the water or reveal their transparent flesh so that light shines through, making others think that they aren't there.

Millipedes are covert operators too. Certain species toss moss or other plants over their backs while they travel.

A biological anthropologist is confirming what many cat people already know—cats grieve over the loss of a loved one much like humans do. And much like humans, letting animals see (and, in a cat's case, smell) the body of their deceased loved one can help give them "closure" and come to terms with the loss.

ravi khemka | cc by 2.0

Why do the leg- (or wing-) work when you can ride? In Stockholm, Sweden, a flock of pigeons has begun taking the subway for its daily trips to a crowded shopping center where the animals like to forage for food. Pigeons have been doing the same thing on the London Underground for years!

This dog takes care of business. After a southwest Ohio couple adopted a dog from an animal shelter, it took only six hours for him to return the favor. The aptly named Hercules chased a burglar from the couple's basement, biting him on the ankle for good measure.

Speaking of canine good deeds—Titan, a beloved dog from Lawrenceville, Georgia, became the first canine recipient of the Neighbor of the Year Award after he got help for his guardian when she suffered from a brain aneurysm and fell, fracturing her skull.

Here's a phenomenon that'll stick in your memory like an octopus sticks to a … coconut shell:

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With the recent discovery that the veined octopus sometimes carries around a coconut shell to use as impromptu shelter, this eight-legged wonder is now the first known tool-using animal without a backbone. According to the biologists who made the discovery, the use of tools to build shelter is such a complicated skill that even some of smartest animals, like chimpanzees, can't do it. (Um, the only self-enclosing "skill" I have is my sofa-cushion fort-building ability, which hasn't been tapped since 1994—so who knows if it's still even in me.)

Octopi are brilliant animals with sensitive short-term and long-term memories and a complex brain, so it's no surprise that their capabilities are extensive and intricate—from mastering mazes to distinguishing between different shapes. And their intelligence runs in their extended cephalopod family. Squids send messages via dermal patterns of light and color, so think twice before you eat calamari again—those are fried little Einsteins on your plate! If scientists have only just now discovered the tool-using skills of octopi, imagine all of the other talents these mollusk marvels and their relatives have got up their tentacles.

Written by Logan Scherer

In high school, P.E. was my worst nightmare. Flickerball, pickle ball, capture the flag: I hated them all and tried my hardest to come up with excuses to sit on the bleachers. The worst periods by far were on fitness-test days—the dreaded mile run. Those were the days when I got really creative with my excuses. One year I faked a bee sting; another year I "got hives" when I tried to run.

Now, despite my phobia of physical exertion and my love of the couch, there are a few things that will get me to do just about anything involving lacing up sneakers and strapping on a pedometer. One of those motivators: animals. Driven by the incentive to save lives, I'm gearing up for an uncharacteristically active winter, undoing all those years of glorious unhealthy inertia by joining the second annual PETA Pack. A group of runners who train together and raise money for PETA, the Pack is the perfect synthesis of fitness and kindness. With the help of professional coach Darren Middlesworth, we'll train together for the Oakland Marathon/Half Marathon/5K on March 28, 2010.

Last year's Oakland Pack.

But you don't have to live in the San Francisco Bay area to participate. Last year, 77 runners from across the U.S. and Canada trained remotely, and those who couldn't make it to Oakland for the big race found a race to run in their hometowns. Together they raised $57,000 for PETA's Investigations and Rescue Fund, and this year we expect to double that figure.

Training begins January 3—the perfect time to make a New Year's resolution a reality. Join today and check the PETA Pack blog for updates.

Written by Logan Scherer

You know, very few things will bother vegetarians like assuming that we eat fish. Um, so, like, what plant is it exactly that you think fish grow on?

By saying "you," I don't mean you, of course. After all, you already understand that fishing hurts, and you're totally down with lobster liberation, right? And you've made it clear to your friends and family where you stand. But they still guilt you into going along to that seafood place they like, saying, "OK, you don't eat fish or lobster, but why can't you have the calamari?"

First of all, "calamari" is one of those nice-sounding words that restaurants use to sell something not so nice—in this case, chopped-up and baby squid. But it can be hard for people to feel a lot of affection for a squid. They live way down underwater, and even baby squid—unlike, say, chicks or piglets—aren't all that cute, to put it mildly. But what they lack in looks is more than compensated for in fascinating ways. If you don't believe me, check out this video:

Anyone who has ever tried to chat up someone in a bar has to stand in awe of the squid's smooth seduction technique, which simultaneously warns rivals to stay away. Not to mention the deep-sea light shows and color-changing camo effects of the jellyfish, octopuses, and cuttlefish that put Industrial Light & Magic to shame. In fact, this stuff is so amazing that you can easily get your friends and family to watch it just for its entertainment value—and then remind them of it the next time you join them for dinner as you explain why you'll all be going to your favorite restaurant instead.