When a volunteer from Antioch Animal Services came into their building and said she saw what appeared to be a sick domesticated ferret on the ground outside in the parking lot, staffers quickly went into action to investigate and corral the little guy to help him.

As it turned out, however, what they found in the parking lot wasn’t one of the playful, mischievous brown-pelted animals but instead one of their wild distant cousins called a mink.

“At first, we did think it was a ferret,” said Melissa Ethridge from Antioch Animal Services. “We kept him warm and comfortable overnight until another volunteer came in and said they thought it was a mink.”

It turns out that minks and ferrets do really look quite alike. They’re both from the mustelid family, along with polecats, weasels, badgers, otters, martens and stoats. Many of these mustelid species can be found in the Sacramento-San Joaquin River Delta region, but most are rarely seen.

Perhaps the most common of the mustelid family familiar to East Contra Costa County residents is the river otter. Ferrets are the only domestic species in the family and are generally lighter brown in coloration. Although the body shape is very similar, mink are likely to have slightly longer tails than ferrets, and their fur is typically sleeker.

“Mink also have a little white on their chin,” Ethridge said. “And it is important to note that mink are a little more aggressive than their playful cousins.”

While you probably won’t usually see mink hanging out downtown, the one at Antioch Animal Services (AAS) didn’t wander very far from its general habitat, said Miriam Klingler. Klingler is an East Bay Regional Park District naturalist who works at Oakley’s Big Break Regional Shoreline, where mink have been seen many times over the past few years.

“The mink could have gotten lost while hunting for food,” Klingler said. “Mink hunt on land and in water.”

She said the little critters are very territorial and that the one at AAS may have shied away from another’s territory while out looking for mice and rats. Mink also eat shrimp and other shellfish. Generally just 20 to 30 inches long, mink have even been known to eat other mink or other members of the mustelid family.

“They are opportunity eaters,” Klingler said.

Klingler also said East County has a lot of competition for food for small shoreline animals such as mink. Along the East County shoreline, it isn’t uncommon to find otters, badgers, beavers, raptors and even coyotes — all part of the same food chain as the mink.

One other difference between mink and the rest of the mustelids is that mink are often raised on farms and are legal to hunt in California for their fur. However, there are many restrictions for hunting the small animal in the Delta region. As far as Klingler knows, there are no mink farms in Contra Costa County.

As with all wild animals that eat mice and rats, mink are susceptible to poisons used to kill critters that they hunt, and Klingler asks that people not use poisons whenever possible. As for the little mink found in the AAS parking area, he was transported to Lindsey Wildlife Experience in Walnut Creek as soon as his biological identity was ferreted out.

Ethridge said the people at Lindsey even needed a few minutes to ensure they had the mink correctly identified before treating him. They later released him back into the wild in the wetlands area behind the Antioch Marina.

“It was very special being there for the release,” Ethridge said. “It was a very happy ending.”

Roni Gehlke can be reached at oakleynow@comcast.net.