I concur with DrasticDreamer regarding elephants…one of my favorite animals.
I think without us knowing animal thoughts, it’s going to be hard to know for certain if they commit suicide. From the outside there are certainly times it looks that way….
I remember reading about a pair of lions in Africa who were thrown out of their pride. They became very very hungry and tried to kill a smaller animal who escaped down a hole in the ground. One lion tried to get in the hole, got stuck. The other lion tried to get it out and couldn’t. The first lion asphyxiated and died. The 2nd lion was found dead 2 days later. He/she refused to hunt and died beside its mate. Grief? Seems so…suicide…don’t know…
Monkey mates will also quit eating and die after a mate dies.
There was also a story about a pair of dolphins had been living for years in the Gulf. And one day the fishermen noticed that the male could not swim properly, and dept floating belly up. The male finally died. The female then continued to push the corpse, trying to get it to the surface to “breathe”. Then a storm came and the body was was smashed into shore rocks. Soon afterward, the female threw herself to the rocks, dying as her partner.
Do they commit suicide? I don’t know, but I think we as humans, always arrogantly underestimate the capacity to love in any other species, but ourselves.