When a tiny kitten shows up on your doorstep, your instinct may be to scoop up the tiny critter and help it. But how can you tell if your new kitten was taken away from its mother too soon?

Holistic veterinarian Dr. Judy Morgan recommends that newborn kittens stay with their moms until they are at least 8 weeks old. "But 10 is even better," she added. By this age, kittens will have been gradually and naturally weaned by their mothers; their eyesight and hearing has fully matured; and they will have learned how to play and groom themselves appropriately.

Here's how to tell if your new kitten was taken from its mother too early.

1. Prone to illness. Newborn kittens get 100 percent of their nutrients from their mother's milk. When they are around 8 weeks old, their mother will wean them from her milk naturally, but if they're taken away too soon they may have a hard time getting the nutrients they need to grow and thrive. According to Hannah Shaw, aka the Kitten Lady, orphaned kittens, or those that are weaned too soon, need to be bottle-fed with a formula designed especially for kittens. Still, even with this formula, very young kittens may not get all of the antibodies they would have gotten from their mother's milk, making them prone to stunted growth and illness.

2. Aggression. Newborn kittens don't just get nutrients from their mother, they also get lessons in behavior from both their moms and their litter mates. Kittens that are taken away from their families too soon don't learn how to play without getting too rough. Morgan recently told us about one of her kittens that had been taken from its mother too soon. "He just doesn't know how to interact with others, is shy and fearful, and quick to bite or scratch when his space is invaded."

3. Fear. Kittens pick up social cues and learn how to respond to humans and other species from their mothers. So kittens that were taken away from their mothers too soon may become timid, shy, and fearful of other animals ... including humans.

4. Difficulty adjusting. As you've probably already guessed, kittens get so much more from their mothers than nutrition. They also get lessons in how to be a good cat. Kittens that are taken away from their mothers too soon may have difficulty learning how to do basic things such as groom themselves and use the litter box. "Some kittens that are weaned early will become 'blanket nursers' or will suckle on strange objects," said Morgan.

The best way to know for sure if your kitten was weaned too early is to get her checked by your veterinarian. Your vet can give you a good estimate of your kitten's age and give you advice and resources on caring for your new kitten and making sure that she gets the best start in life.