Suddenly, the pet disappeared.

I enjoyed the game in survival mode until around 3 a.m., ended the game in the right place, and logged on at 12 p.m., but the wolf and parrot that I had tamed disappeared. It was never a sitting motion anywhere, nor was it a situation where I died before turning it off. I looked around, turned off the game, and rebooted my phone, but it didn't return. What's going on?