Was wondering that very thought lately.
https://wol.jw.org/en/wol/d/r1/lp-e/102006163?q=animals+live+forever&p=par
https://wol.jw.org/en/wol/d/r1/lp-e/2015008?q=animals+live+forever&p=par
Why do animals experience deformities, sickness, and death, just as humans?
The notion that God will "restore" human biology to eliminate death, but will not do the same for animals, is absurd.