The 5-week-old pups have remained highly dependent on their caretakers since they were found at a residential construction site in Titusville, Florida.

When the den was found, an adult otter ran off and didn't return, WFTV reported.

"(They’re) doing well, but their condition could change at any moment," said Tracy Frampton, the hospital’s executive director. "No matter how hard we try, Mom does a better job than we do."

>> Photos: Rescued otter pups

If the otters survive the critical early period, they’ll be moved to an outdoor enclosure with a pool and fed live food sometime around July or August.

Frampton said the hospital is in need of donations. The cost of raising each otter is about $2,300.

"If you find otter pups in the wild, leave them alone," Frampton said. "As tempting as it is to intervene, their mom is probably nearby and returning shortly."