Scorching heat is the defining feature of desert landscapes, making life relentlessly difficult for their inhabitants. Animals in these ecosystems often adjust their routines, maximising foraging during the cooler hours of dusk, dawn, or night. But when everyone adopts the same strategy to escape the heat, it triggers the chaos of competition, where smaller, weaker species often risk being outcompeted or pushed towards extinction.
Photo: Dr. Anish Andheria
The challenge intensifies when you happen to be the most delicious meal for nearly every predator around you. That’s when you realise your greatest enemy isn’t the blistering heat of the day, but the comfort and danger of a cooler night. Mastering life in the heat gives you a competitive edge to outwit your predators that only hunt under the cover of darkness.
The threatened Indian spiny-tailed lizard learned it through its evolutionary journey, becoming one of the few desert creatures that chooses the peak blazing hot hours of the summer to find its food.
This remarkable creature has evolved ingenious survival strategies, perfectly adapted to its landscape. Due to the energy-intensive nature of hunting in the heat, the lizard has adapted to a primarily herbivorous diet, feeding on grass leaves, stems, and tender shoots. Nevertheless, extended observation of these creatures reveals a different reality. When the monsoon brings an abundance of protein-rich insects, this supposed herbivore seizes the opportunity to indulge in nutritious invertebrates. It’s a pragmatic approach to survival in a harsh environment, where making the most of every opportunity is crucial.
As the saying goes, don’t take pride in an idea just because it came to you; chances are, others have thought of it too. This rings true even in the wild, particularly with some raptors, who have learned to forage in the peak heat of summer. Quoting the concept of evolutionary arms races in ecology: if your predators can fly and spot you from a mile away, you’d better learn to run like hell if you want to survive. The spiny-tailed lizard belongs to the Agamid family—a group of lizards known for their powerful hind limbs, which enable them to accelerate at a surprisingly fast rate so that all you often see is a trail of dust left behind.
Though the speed often saves it from predators, it still has to deal with the blistering heat and the scorching sand during the day. Its body is covered with protective scales that help shield it from the heat, and it is often seen standing on its forelimbs with only the tips of its claws touching the ground—neatly minimising contact with the hot surface. The Indian spiny-tailed lizard excavates a criss-cross network of underground tunnels in soft, binding soil, where temperatures remain significantly lower than the sweltering conditions above. Its burrow is unique and easily distinguishable from those of other burrowing animals in the landscape, thanks to its crescent moon-shaped entrance. While resting inside, the lizard curls its spiny tail at the entrance and seals it with soil, effectively blocking intruders and keeping the burrow both cool and safe.
Photo: Dr. Anish Andheria
Building a shelter is an essential survival skill in the harsh desert conditions full of predators. As soon as they begin foraging with their mother, young spiny-tailed lizards also start learning to dig. Breeding begins in February, and by June or July, tiny offspring are seen darting through the grasslands. Even during the hottest months, they remain strictly diurnal, active from dawn until dusk. On sunny summer days, they are most active until early afternoon, while on cloudy days, their activity may extend into the dusk hours.
The Indian spiny-tailed lizard plays a vital role in the desert food chain. Its high glycogen and fat content make it a key prey species for many terrestrial and aerial predators. Raptors such as harriers and falcons are often seen feeding on them, while juveniles are vulnerable to predation by smaller birds such as the white-breasted kingfisher.
Not just birds—other reptiles also take advantage of this energy-rich food source in the resource-scarce deserts. The red sand boa, a common snake in the Thar, is one of the main reptilian predators of the lizard. It has frequently been observed pulling lizards out of their burrows. When attacked inside its burrow, the lizard has few defences apart from anchoring itself with its strong claws, resisting extraction. For the red sand boa, dislodging a lizard from its narrow tunnel requires considerable time and strength, but the high-energy reward makes the effort worthwhile.
Among mammals, the crepuscular Indian desert fox is a known predator of the spiny-tailed lizard within its natural range. Unfortunately, humans have added another predator to the list. Human-subsidised free-ranging dogs are now frequently seen roaming in their habitat, digging up burrows and pulling vulnerable lizards out to feed. These dogs are becoming an increasingly serious threat to this already vulnerable species.
With such a diverse set of predators across trophic levels, the Indian spiny-tailed lizard has evolved several anti-predatory adaptations. Though it lacks offensive defence mechanisms, its coloration blends remarkably well with the desert surroundings, offering effective camouflage. Interestingly, there are observable variations in coloration between populations in western Rajasthan and those in the salt plains of Kutch. In Rajasthan, individuals often exhibit a steel-blue hue along the lateral scales of the tail and hind limbs, both features absent in Kutch populations. Further research is needed to determine whether this phenotypic variation stems from genetic diversity or is linked to differences in diet and vegetation between the two landscapes.
If camouflage fails, the lizard relies on speed. These lizards are extremely vigilant while foraging, especially when accompanied by their young. Adults frequently forage with their heads raised high on their forelimbs, scanning the surroundings with their tails arched. They typically stay close to their burrows, and even a slight disturbance can send them sprinting back to safety.
Yet, neither camouflage, speed, nor vigilance are enough to protect the Indian spiny-tailed lizard from the most persistent threat—humans. The species is categorised as vulnerable in the IUCN Red List, and is listed under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). As per the TRAFFIC 2004 report, between 1997 and 2001, a total of 2,15,838 specimens of various spiny-tailed lizard species were traded internationally, with the Indian species (Saara hardwickii) accounting for just 2% of that trade. However, recent seizures within the country indicate a high level of local consumption, suggesting intense domestic demand for the species.
Locally known as sanda or sandho, this lizard is widely hunted for its fat, which is traditionally believed to cure impotence and is consumed as an aphrodisiac. Adult lizards are dug out of their burrows, immobilised by breaking their backbones, and boiled to extract fat. Additionally, their meat is considered a delicacy in several communities within their range.
Well, it’s not just hunting that threatens the Indian spiny-tailed lizard. Even in a hypothetical scenario where hunting is entirely stopped, the species still faces a severe threat from climate change. Although adapted to the extreme heat of desert environments, as a reptile, the lizard relies on behavioural strategies—such as basking in the sun or retreating into burrows—to regulate its body temperature. These adaptations come with physiological limits to how much heat the species can tolerate.
A recent study published in the journal Biology Open revealed that if the world continues on a high-emission trajectory (SSP5-8.5), the rising temperatures by 2099 could drastically impact this species. The study estimates that climate change could reduce the lizard’s foraging activity by up to 43.5%, severely limiting its energy intake. Additionally, its sprint speed may decline by 14.5%, making it more vulnerable to predators. The lizard may also be forced to spend up to 9 hours a day inside its burrow to avoid lethal surface temperatures, restricting essential behaviours such as foraging, basking, and mating. Since the Indian spiny-tailed lizard already lives near its upper thermal limits, even modest temperature increases could push it beyond its survival threshold.
The question remains: can the Indian spiny-tailed lizard, despite all its evolutionary advantages, outrun the looming threat of extinction in a world where natural habitats are shrinking under urban expansion, biodiversity is neglected or hunted, and the climate continues to change amid inadequate efforts to curb emissions?
Disclaimer: The author is associated with Wildlife Conservation Trust. The views and opinions expressed in the article are his own and do not necessarily reflect the views and opinions of Wildlife Conservation Trust.
Your donations support our on-ground operations, helping us meet our conservation goals.
Related Links
- Heater of Hope I English
- Weird Connections – Part II
- Man’s best friend, wildlife’s NEW foe!
- Scaling up Pangolin Conservation in India
- How a Water Heater Can Change and Save Lives
The post The Indian Spiny-tailed Lizard:A Runner of the Thar Losing Its Race Against Time appeared first on Wildlife Conservation Trust.
