I lived in Texas in 1972, I remember discussing Chubbies with the ranch hands then.
Can you remember if the description of the critter back in the '70s resembled what's been reported since 1995? This guy's theory is that what people have reported seeing has changed over time and place with the 1995 Puerto Rico events introducing bipedalism and the spikey back.
Perhaps the only thing these sightings have in common is the 'go-to' name Chupacabra . . . a sort of latin Boogeyman.