“The lizard brain is hungry, scared, angry, and horny ... the lizard brain only wants to eat and be safe ... the lizard brain will fight (to the death) if it has to, but would rather run away ...” — Seth Godin

By CAMERON BARROWS

True, and yet a lizard’s brain is capable of so much more. While survival and reproduction are among a lizard’s top priorities, how they achieve those objectives can reveal the depth and breadth of what a lizard brain is capable of. Take the seldom seen desert night lizard. These diminutive lizards can live more than 10 years under the debris from fallen Yucca branches or beneath Agave clones, live in extended families (kinship groups), and give birth to live babies (not eggs) using a placenta-like interface to nurture the growing, not-yet-born neonates from their mother’s blood supply. Being relatively long-lived the dominant males and females and their young almost certainly create lasting pair bonds.

Also long-lived, chuckwallas live in socially structured groups. Dominant males defend a territory from trespassing interlopers from adjacent territories, and from “rogue” non-territory holding males looking to displace the current dominant male.  Within his territory the dominant male protects one or more adult females as well as sub adult, subordinate, males and females. Adult females will have selected a given male based on his overall body size and especially the size of his tail, both being accurate measures of the quality of food resources to be found within the male’s territory. As these lizards can live more than 20 years, perhaps up to 30 years, they can form long-lasting male-female bonds. However, if a male has a good territory with plentiful food resources he will likely have a harem. From the adult females’ perspective, in a harem they live under the protection of the dominant male within a territory with ample food resources. That means they do not have to fend off unwanted suiters, do not have to defend their own territory, and live within a group with many eyes that can then warn each other of the danger that interlopers and especially predators (often birds of prey) pose.  Fending off an unwanted suitor means her attention will not be focused on looking for possible predators and so she and the unwanted suitor are at a much higher risk of becoming prey. Having one dominant male who keeps other suiters at a distance may have some definite advantages.

Subadult males and females within the territory may be the offspring of the dominant male and females and can also benefit from the protection of the dominant male and the “many eyes.” The subadult females may opt to stay or eventually move into another territory if they perceive the “grass is greener” elsewhere. The subadult males are biding their time, waiting for the dominant male or an adjacent territory holder to pass away or succumb to a red-tailed hawk or prairie falcon. Even if the dominant male survives such an attack, if he loses his tail, either to a predator of through a fight with a challenging male, he will then loose his dominant status and will be usurped by a male with an intact, large tail. However, although it may take a couple years, that once-dominant male can re-grow his tail and can then potentially reassert his authority.

Being long-lived helps but is not a requirement for establishing long-lasting male-female bonds. Side-blotched lizards may live just one to two years, yet they too have developed a relatively complex social network. In their case, the type of bond they establish is dictated by their DNA and is expressed by the color of the adult males’ throats. Their throats come in three colors, blue, orange, and yellow, although some have hybrid mixed orange and blue throats. A blue throated male defends a small territory and forms monogamous bonds with a female that will be his mate for the extent of his short life. Orange-throated males, even orange-blue hybrid throats, are somewhat like male chuckwallas in that they aggressively defend large territories encompassing a harem of females. Yellow-throated males are the least aggressive, and do not establish territories. Rather, looking and acting much like females, the yellow-throated males can infiltrate an orange-throated male’s territory and mate with one of his harem members when the orange-throated male’s attention is focused elsewhere. All three throat colors are successful, “playing” what the researchers who discovered this system called a game of “rock-paper-scissors.” Blue-throats, with their monogamous lifestyle, are vigilant and keep yellow and orange-throats away. However, orange throats with their harems sire more offspring. Yellow-throated side-blotched males don’t have much success in mating with females in blue-throat territories – the blue-throated males are too solicitous of their monogamous females.  But those yellow-throated lizards are successful at mating within orange-throated males’ territories and do so without the energetic cost of sustaining a territory. From year to year the prevalence of orange or blue or yellow-throated males shifts. The researchers surmised that shift was catalyzed by the changing preferences of the female side-blotched lizards.

The lizards’ “reptilian brain” does not appear to limit their ability to engage in mating systems that run the gamut of mating approaches found in mammals with their “more developed brains.” Even in our human species, if one searches through the various cultures and religious sects across our planet, there are parallels with each of the lizard mating systems I have described here. We humans keep looking for the “moral high ground” compared to the rest of nature. So far, we have yet to find it.

Nullius in verba 

Go outside, tip your hat to a chuckwalla (and a cactus), think like a mountain, and be safe