Being aggressive or playing rough with your pets or other animals is something that toddlers and younger tykes commonly do because of their constant trial-and-error and touch-to-learn processes. Soft or course fur, different-looking body parts and different sounds make a pet a learning wonderland for your little guy. However, it is definitely something to correct and look into if it persists due to the threats to both animal and child.
Be consistent. Sure, it's the first rule in disciplining, but it's also the most important. Whichever method you choose to discipline with when your child is acting inappropriately with animals, stick to it every time.
Take your toddler's hand firmly when she hits, grabs or pulls on the animal and make her hand gently pet the animal while saying something along the lines of "Only nice touches for the dog/bunny/kitty." The action is what your child will understand first, particularly if she's not of talking age yet. Being corrected and shown the proper actions when acting in an inappropriate way is a key learning experience for young toddlers.
Show your tyke how to love on the animal without being rough while still learning, no matter what age. Children of all ages learn from example, so this will help your family pet out with the rough antics of a learning toddler or rowdy preschooler. Even if you're not always overly affectionate with your four-legged friends, take the extra step every now and then when your pet and child are in the same room to gently pet your dog, cat or other pet while talking in a soft, soothing voice. Just as the saying goes, actions speak louder than words, especially to a little toddler or preschooler who is learning how to talk and behave!
Talk to your child, particularly if he's an older toddler capable of understanding words, explaining to him that animals need to be touched and loved just like he does and that there are certain dangers involved with hurting an animal. While you don't want to scare him, he may not quite understand that animals only have a few sounds of warning and their teeth to defend themselves; they can't use their words like people can.
Remove your child from the pet, especially if rough behavior continues after a firm "NO!" or other firm command that your child understands.
Use the same disciplinary behaviors you use for other misbehavior. For example, if your child receives time-outs for other misbehavior, continue this with her when she's rough to the furry creatures she encounters.
Allow your furry family member to get away if it needs to by removing it to another room outside the reach of your rough-housing tyke, trying your best not to make the animal feel as though it's being punished. Most animals have a "safe place" in the home, such as a room they prefer to sleep, the backyard or even a cage. Comfort your pet while removing it from your child's presence.