"Perhaps you'd be interested if I had a sponge?"

Male Humpback Dolphins Woo Mates By Presenting Sponges as Gifts

They also use "wingmen" and occasionally sport the sponges as hats—but researchers aren't sure just how much game they really have

Floating sea pen designed to hold captured vaquitas

Critically Endangered Vaquita Porpoise Dies After Capture in Latest Rescue Effort

Conservationists are attemping a risky last-ditch plan to move the remaining creatures to a sanctuary in the Gulf of California

One of the mine-hunting dolphins being retrained to find vaquita porpoises

Mexico Will Use Dolphins to Herd the Endangered Vaquita to Safety

Mine-hunting dolphins will help researchers transfer the remaining creatures into marine sanctuaries

U.K. Killer Whale Contained Staggering Levels of Toxic Chemical

Lulu had one of the highest concentrations of PCBs ever recorded in a marine mammal

Orcas Are Killed in Front of Tourists, Now Caribbean Nation Wrangles With Whaling Laws

The prime minister of St. Vincent will introduce legislation to outlaw orca hunting

Smithsonian researchers found that otters that use tools aren't closely related.

Unlike Dolphins, Sea Otters That Use Tools Are Not Closely Related

Rock-bashing in otters is a very old behavior

This diminutive mammal could soon go extinct.

Only 30 of the World’s Most Adorable Porpoise Are Left on Earth

As “the panda of the sea” hurtles toward extinction, scientists stage a last-ditch effort to save the species

Nearly 100 false killer whales are currently stranded in the Everglades in the worst Florida stranding of its kind.

Scores of Dolphins Are Stranded in the Everglades

So far, at least 82 false killer whales have died

The fossil Arktocara yakataga (resting on an 1875 ethnographic map of Alaska) belonged to a dolphin that swam in subarctic marine waters around 25 million years ago.

Smithsonian Researchers Uncover Extinct, Ancient River Dolphin Fossil Hiding in Their Own Collections

Sometimes, paleontologists don’t have to go into the field to discover a tantalizing new species

Artist's rendering of the first U.S. dolphin sanctuary

National Aquarium Will Move Dolphins to Seaside Sanctuary by 2020

Under mounting public pressure, the aquarium's eight bottle-nosed dolphins will soon move to a seaside retreat in the tropics

Does Snot Help Dolphins Echolocate?

The cetaceans can perform acoustic gymnastics, but how they produce ultrasonic noises has long eluded scientists

Groggy after a night in a strange place? A night watchman in your brain may be to blame.

You Can’t Sleep While Traveling Because Your Brain Acts Like a Dolphin’s

On the first night in a new place, half your brain stays awake to watch out for danger

This Is How Dolphins 'See' Humans With Echolocation

A news study capture images of what dolphins 'see' underwater

Electric Fishing Puts a Rare Dolphin-Human Partnership at Risk

Illegal fishing practices are threatening traditional cooperation between humans and river dolphins in Burma

Wild pigs go for a dip off Big Major Cay in the Exhumas, Bahamas.

Not Just Dolphins: Where to Swim With Pigs, Penguins and the Gentlest of Sharks

At these beaches, splash around with some more unusual creatures

Shortly after the 2010 Deepwater Horizon spill, dolphins were observed swimming through an oil slick. Their exposure to petroleum fumes may have wrought serious consequences.

Research Confirms Fears that Deepwater Horizon Spill Contributed to Dolphin Deaths

Dead bottlenose dolphins stranded in the Gulf of Mexico had lesions linked to petroleum exposure

These Dolphins Mourn Their Dead

A new study looks into a sad ritual at sea

An albino bottlenose dolphin, like this one but without its melanin, was spotted off the coast of Florida in December.

An Albino Dolphin Was Spotted Off the Coast of Florida

It is only the 15th albino dolphin sighting recorded by the National Oceanic and Atmospheric Administration

Our Answers to the Most Burning Questions of 2014

Here are the ten most popular installments of "Ask Smithsonian" this year

Elusive Indus River dolphins.

Why Freshwater Dolphins Are Some of the World’s Most Endangered Mammals

In Pakistan, dams and drainage has reduced the endangered Indus River dolphin’s range by 80 percent

Page 4 of 5