What is the purpose of spines on claspers sharks?

* Protection: The spines on claspers help to protect the male shark from injury during mating. When the male shark inserts his claspers into the female's vent, the spines help to prevent her from biting or damaging his delicate reproductive organs.

* Stimulation: The spines on claspers may also help to stimulate the female shark during mating. By providing sensory stimulation to the female's genitals, the spines may help to increase her arousal and readiness to mate.

* Grip: The spines on claspers also help to ensure that the male shark can maintain a firm grip on the female during mating. By anchoring the male's claspers to the female's body, the spines help to prevent him from slipping out during the crucial moment of fertilization.