How to increase FPS declined by skin mesh related draw call on iOS platform?

We’re developing an iOS game. FPS declines sharply when we increase the number of skin-meshed characters. 40 characters will bring about 20 FPS more or less. Any solution for handling this problem? Thanks experts in advance.

If it’s a mobile device, compress the character models to lesser polygons. 1500 polys are 3000 tris. 3000 tris * 40 characters = 120k tris in the scene.
Someone had a rather related question about the polycount for mobile games: polycount IOS / Android games? - Questions & Answers - Unity Discussions