Okay. We have a gaggle of geese, a murder of crows, a pack of wolves...

How about this then:

A torpid of turtles.

That's my new word for a group of turtles.

Here are some more:

A habit of nuns.

(Not that nuns are animals, but we can do some new words for groups of people too. Why not?)

A hornet of rhinos.

A leaping of lizards.

A stringwiener of dachshunds.

Go to it...see what you can come up with.