Dart and dart retainer

A dart comprising

• a body, the body defining a chamber having a plunger and a striker pin located therein, the striker pin configured to operatively strike a primer for actuating the plunger when the dart hits an animal to operatively deliver a substance through a hypodermic needle extending through a front end of the body, and
• a retainer comprising a barb body locatable on the hypodermic needle characterised in that the barb body is threaded which prevents the dart from being dislodged from the animal until the dart is removed by a user while allowing the user to remove the dart when the animal is inhibited by imparting rotational force resulting in minimal damage to a tissue and skin of the animal.