Fleas are small, wingless insects that feed on the blood of animals and humans, are capable of jumping up to 200 times their body length, and can transmit diseases like the bubonic plague. A female flea can lay up to 2,000 eggs in her lifetime, and they can survive for months without a meal while the life cycle from egg to adult can be as short as 14 days under favorable conditions.  

The flea life cycle has four stages: egg, larva, pupa, and adult. After a blood meal, a female flea can lay up to 50 eggs per day, for a total of up to 2,000 in her lifetime. From egg to adult, the life cycle can be completed in as little as 14 to 28 days, depending on conditions. Adult fleas can live for up to a week without a blood meal and can go for over 100 days between meals if they are not moving. Fleas feed exclusively on the blood of warm-blooded animals, including humans, dogs, cats, and rodents. They are known to transmit diseases such as the plague and murine typhus. Flea bites can cause intense itching, and some pets and humans can develop an allergy to flea saliva, leading to severe irritation. Fleas can also transmit tapeworms to their hosts.