Both present distinct sets of challenges to their owners, especially during breeding season. For more information on breeding season, please visit our Breeding Season Issues page. At maturity, males show several secondary sexual characteristics. One of the most easily identified is the large jaw muscles on either side of the lower jaw, below the ear. Males have large, blocky heads, and the jowls add to this effect.
Males also have two fatty deposits on their forheads, behind the eye and above the ear.
These also add to the size and blocky shape of the head. Here is a photo of Jake, a mature male. Notice the fatty bumps behind the eye and above the ear. This is Brownie, who is also a mature male. This photo, taken from underneath the chin, gives a great view of the swollen jowls.