The animals in Dr. Vacanti's lab are on the cutting edge of regenerative medicine.
"We actually used human cartilage cells in a human ear shape and then on the back of this mouse," said Dr. Vacanti. "The human cartilage cells grew into a human ear."
Within a year he plans to re-grow an ear on a human in a similar way.
"We can give somebody back their own face that's been either ravaged by cancer, destroyed by a terrible accident or injured by war," said Dr. Vacanti.
Pigs are huge helpers when it comes to healing.
Believe it or not, their genetic makeup is pretty close to humans," said Dr. Samer Mattar, Clarian Bariatrics.
Surgeons use material made from the pig's small intestines to repair torn muscles caused by hernias.
Pig powder is re-growing severed fingers at the University of Pittsburgh. A substance, made from a pig's bladder, helped a man's finger go.
The simplest applications involve just being able to spread a powder or a particular form of the powder on the wound site so it can affect the wound healing process," said Dr. Steve Badylak, DVM, Director of McGowan Institute for Regenerative Medicine in Pittsburgh, PA.
From land to the sea, fish are helping scientists fix hearing disorders. If zebrafish lose hearing, they naturally re-grow new auditory cells. Scientists are studying the genetic process to restore hearing in humans.
"So our hope is that we can actually end deafness," said said Dr. A. James Hudspeth, Howard Hughes Medical Institute.
The research is allowing animals and people to help each other.