This is not technically correct, but it is acceptable so long as there is an implicit understanding that our discourse is suitably limited in this case, limited to talk about animals. All dogs are mammals. No reptiles are humans. All dogs are mammals. No reptiles are humans.
All lonely people are prone to exploitation by others.
Certain species of whales are in danger of extinction. Some court procedures are so complicated as to be very inefficient. No Russian authors are insensitive to nature. The ozone layer around the earth could be damaged by frequent use of aerosol spray cans. Use conversion, obversion, and contraposition to determine whether the following arguments are valid.