The pet industry is peculiar.
There are huge players like the Mars corporation, Colgate-Palmolive, Rayovac
they dominate the commodities end of the business.
Then you have the second tier companies that exist in both pet specialty stores as well as independent pet stores. Many of these companies also maintain secondary brands for sales to walmart, grocery, and smaller mass stores like Walgreen, rite-aid, Kroger, etc. These companies typically carve out a particular Niche in what is already seen as a niche industry.
And below that are the smaller companies and boutique manufacturers that are typically only sold in independent pet stores. These are usually the high design/high quality/ low volume Companies that couldn't survive the pricing structure of the distribution chains of the rest of the industry.
Finally you have the direct from Asia sourcing which is a huge part of the industry.
The best way to find out about any of them is to get out to petsmart, petco, target and independent pet stores.
You can learn about the needs of the industry simply by keeping pets.
I think the most exiting thing about designing in the pet industry is that the products and categories are so varied that there is no limit to the types of materials and processes that you get to explore.