all animals are equal discussion

Singer argues that there is no moral justification for denying moral consideration to animals. Can you think of a good moral reason why our moral consideration should include all humans, even those without the ability to reason yet denied to all non-human animals (some of whom have that ability)? What response might he have to your way of drawing the line between the types of beings that should get moral consideration and those that should not?

source is below and also uploaded:
Singer, P. (1989). All animals are equal (Links to an external site.)Links to an external site.. In T. Regan & P. Singer (Eds.), Animal rights and human obligations (pp. 148-162). New Jersey: Prentice Hall. Retrieved from http://spot.colorado.edu/~heathwoo/phil1200,Spr07/singer.pdf