Diastema are found in

The correct option is rat.

What is a diastema?
A diastema is a space or gap between two teeth. In veterinary anatomy and zoology, it refers to a naturally occurring gap or toothless space between different types of teeth, most commonly between the biting teeth (incisors and canines) and the chewing teeth (premolars and molars).

Dental Formula and Diastema in Rats:
Rats are rodents, and their dentition is highly specialized for gnawing. A rat's dentition consists of one pair of upper and lower incisors followed by three pairs of upper and lower molars. They completely lack canine teeth and premolars. The absence of these teeth creates a prominent, wide gap between their sharp, continuously growing incisors and their grinding molars. This natural gap is the diastema, which allows rats to pull their cheeks inward to seal off the back of the mouth, preventing debris or inedible material from being swallowed while they gnaw.

Comparison with Humans (Man):
In humans (man), the normal adult dentition consists of incisors, canines, premolars, and molars arranged in a continuous, unbroken arch without any natural gaps between different categories of teeth. While spacing can occur in humans due to developmental issues or dental alignment variations, it is not a characteristic, natural anatomical feature of the human dental formula.

Therefore, diastema are naturally found in rat and not in man.