A: From your description, my first guess would be to suspect a rat. Literally, a roof rat called Rattus rattus. I know that is scary thought but we have many more of these rodents than most of us would like to admit. They come out at night (nocturnal) and eat fruit remaining on trees. Actually, they are omnivores; which means they eat insects, lizards as well as plants but fruit is their favorite food. Roof rats are very destructive and can gnaw through wire, pipes, walls, etc. Poisoning them can be dangerous to other animals we desire to keep such as our family pets. Traps could be set at night when birds and other creatures are not active to avoid capturing beneficial animals. However, some of our furry friends (cats) are active at night and might be too curious to avoid the trap. If these options seem unacceptable, consider talking to a professional pesticide company. They can inspect the area for signs of the rats and determine the best course of action. Metal guards can be placed around the base of the tree to discourage the gnawing and climbing into the tree. Snakes and predatory birds are excellent rat hunters so be careful to leave these creatures alone as they help keep rat populations in check.
Q: Some animal is gnawing on the trunk of my citrus trees. What could it be?