Most Western art shows are open to North American wildlife species. Western Art Shows have generated more sales for me
than strictly wildlife shows by a lot!
Here are some animal specific shows that I am aware of:
Society of Animal Artists Annual Exhibition- shows held in museum venues, juried to become a member and the show is also juried. A percentage of work goes on tour to 4+ museums for a year. High prestige and great for resume - however you must be a member of SAA to even enter. Many people don't sell all that well (most people don't go to a museum to buy artwork), but I have sold my work 3 out of the 4 years I have been in.
Artists For Conservation (AFC) - much like SAA show above. I am not a member, so don't know the specifics, but they do both a live exhibit and an online one each year.
Birds In Art - Limited to birds as a subject matter and must be completed in past two years. BIA is another great one for the resume/prestige, but the show is HARD to get into. I have gotten in one out of four years that I have submitted. If you get in you GO to the show - everything except your travel is paid for! While a super high quality show sometimes it feels like a crap shoot getting in with many outstanding works getting rejected from top wildlife artists and sometimes works that I don't think are that great get in
April entry deadline.
OVAL Kentucky National Wildlife Exhibition - Limited to North American Species and the show is only held every 2 years (even years). They give out over $10,000 in awards. Fall entry deadline.
LSU Animals In Art - January Entry deadline. I have sold one work at this show (small one).
Art Show At the Dog Show - January Deadline. Lots of awards. Limited to dogs as a subject matter.
Bennington Center For the Arts "Art of The Animal Kingdom" - must be invited to submit work (you can e-mail to find out about how to get invited) and then work is juried as well. Nice venue. I have sold one work there in three years.
American Academy of Equine Art - Horse specific subject matter. Fall deadline. I have sold one work there.
As far as sales type shows
I know Nature Works is one that generates a lot of sales - hard to get into and you must be invited. Openings do not become available very often. It is in Feb. in Oklahoma each year, but as I can't get into it (yet) I don't know specifics.
Southeastern Wildlife Festival (SEWE) - some people do really well here and others don't. I have not participated. Must apply and be accepted.
Easton Waterfowl Festival - similar to SEWE - some people do really well here and others don't. I have not participated. Must apply and be accepted.
Dallas Safari Club - no experience, expensive to enter. Some do well, most new artists do not (from what I have heard).
There are a LOT of western art shows and most will accept horses and NA wildlife. The western shows fit a wide range of pretige and difficulty to get into. A lot of the higher end shows will require you to have the right connections to get into (and you make these connections through galleries and mid-level shows - you make the connections for the mid-level shows through lower end shows or juried shows)... in the art world it truly isn't just about what you do but also who you know!