Many vertebrates such as fish , birds and amphibians do not suffer presbycusis in old age as they are able to regenerate their cochlear sensory cells , .
Mammals including humans have genetically lost this regenerative ability .
Many vertebrates such as fish , birds and amphibians do not suffer presbycusis in old age as they are able to regenerate their cochlear sensory cells , whereas mammals including humans have genetically lost this regenerative ability .