Pets icon is included into Science Icon Set. You can view all icons here:[link]
These icons are available in sizes 16x16, 24x24, 32x32, 48x48, 128x128 and 256x256. They are provided in two color solutions: 256 colors or True Color with semi-transparency. The icons come in ICO, PNG, GIF and BMP formats.
Download link: [link]