Here are some interesting environmental links folks are Digging today:

The Independent: "Final cut for Hollywood's favourite dog"

Sealyham terriers were once all the rage, becoming fashion icons sported by stars like Humphrey Bogart, Cary Grant and Alfred Hitchcock. But after the U.K. banned tail-docking — common practice since Sealyhams were first bred in the late 1800s — the breed waned in popularity, and now even faces extinction. I can't help but wonder, though, why this matters. It's not a species; it's just one manmade breed that has no ecological value. No individual animals would suffer, and if no one's buying them anymore, who cares if they go extinct?

Wired: "Oldest Animal Fossils Discovered"

— Sedimentary deposits mined in Oman have yielded evidence of the oldest animal ever known, an underwater, spongey progenitor that some scientists believe gave rise to all current life on Earth. The fossils date back 635 million years to the Cryogenian period, so-named for the suspected "snowball Earth" conditions at the time.

New Scientist: "What's the point of being warm-blooded?"

— Reptiles are much more energy-efficient than birds and mammals, since they only heat up their bodies enough to perform their basic duties. Warm-blooded animals keep their internal thermostats cranked up all the time, however, generating constant heat that's mostly wasted. This has long baffled scientists, and most theories, such as warm-bloodedness arising for stamina's sake, have holes. But a new study could answer the question, suggesting the first endotherms were herbivores, not carnivores as long assumed. Since an all-leaf diet is heavy on carbon and low on nitrogen, herbivores just eat more leaves and burn off the extra carbon as heat, the study's authors write.

SEED: "The Future of Humanity is Linked to the Fate of Our Cities"

— Cities are the epitome of the human spirit, according to SEED, as they manifest our desire to grow, innovate and build wealth in groups. And 2008 was a big year for urban centers, as more people lived in them than not for the first time in history. While this is good news for creativity and innovation — doubling the size of a city usually increases its wages, wealth, number of patents and educational resources by 15 percent — it could be bad news for Earth. Doubling the size of a city also increases crime, disease and pollution by 15 percent. How we build our cities, SEED says, could determine our species' future.

• LiveScience: "'Seuss-like' Sea Creatures Discovered"

— Scientists exploring a marine reserve near Tasmania have found three new species: a barnacle, a sea anemone and a type of carnivorous sea squirt that traps its prey with a funnel-shaped section of its body, much like how a Venus flytrap hunts.

Russell McLendon

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.