It’s just more efficient that way. Nipples are one of the body parts that everybody gets issued early in life.
They’re formed during the first fourteen weeks of development in the womb. The fact that everyone gets them sort of makes sense, since they begin growing before male or female hormones start flooding the fetus and instigating the development of sexual organs and other gender-based characteristics.
Nipples are interesting things. While some argue that nipples and hair are what make mammals distinctively mammalian, that’s not entirely true.
For starters, there are exceptions in the mammalian world, like the monotremes the duck-billed platypus and the spiny anteater of Australiathat lack mammary glands and nipples in both the males and the females. Instead of the usual arrangement, the mothers excrete milk through pores in the skin, and the young lap it off their fur.
Secondly, there are a few male mammals that don’t have nipplesthe stallion and the bull, for example. This may be because the mammary glands of the females of these species exist back between the hind legs.
In the males, there’s simply no room to develop nipples therethey have other, more important equipment that needs the space in that spot.
The bottom line is that nipples on males serve no apparent purpose. However, the romantic within us wants to believe that they’re there to remind us that the genders are not so different after all. Group hug!