The Corvan gilvos were a stick-like animal indigenous to the rainforests of Corvan II. Gilvos were uniquely suited to live in trees, as they closely resembled a tree branch. Their habitat was threatened by industrial pollutants on Corvan II, and by 2368, only fourteen specimens remained.
That year, the USS Enterprise-D transported two gilvos to the protected planet of Brentalia. The gilvos were momentarily threatened by a fire that broke out aboard the ship during their transport in the biolab, but Commander William T. Riker was able to save the animals (at Alexander Rozhenko's insistence). (TNG: "New Ground")