Repto-Humanoids were a warp-capable humanoid species from the Delta Quadrant. They stood upright and had a skeletal system similar to Human beings. However, they were cold blooded, resembled a reptile and they reproduced by laying eggs. They nested their eggs on Planet Hell which contained vapors that their young fed on.
While researching the planet, in 2372, Tom Paris and Neelix, who were at odds over Kes, were forced to seek shelter in a cave and seal it from the vapors of the planet. They discovered a nest of eggs, from which a baby repto-humanoid hatched. But it was weakened, and they realized that it needed the amino acid vapor of the planet to survive. They put aside their differences and took the baby out from the cave, and the baby began to regain its strength. After bonding over their concern for the welfare of the creature, they refused to be beamed up by USS Voyager until they were sure the creature was safe. Once one of the hatchling's parents returned and took the baby, Paris and Neelix beamed up with a new understanding of each other. (VOY: "Parturition")