Triglycerides in animals bodies are usually solid fats, and those in plants are usually oils. However, many animals living in the arctic and antarctic have a greater number of triglycerides that are oils than do other animals. What advantage would the storage of body fat as oil instead of solid fat be to animals that live in freezing climates?
Their environment is the clue. Oils are liquid at room temperature i.e. they have a lower melting point so they don’t become solid in the animal. If they did the animals’ tissues would rupture.
Fats aren’t solid at body temperature.