There cuckold of Texas (Phrynosoma Coronatum), present in desert areas of North America, is able to spray its own blood From the eyes up to 1 meter away to discourage predators. About six species of this animal, no longer larger than 20 cm, implement this defense strategy Very bizarre and almost macabre. The cuckold lizard, also known as corneous toad, has a flat body, a leathery skin rich in horny growths and a camouflage color. In front of the predators, they tend to escape or hide or, rarely spray blood from the eyes, such as Last resource. This behavior above all discourages predators such as Coyotes and other canids, probably because of some repellent substance present in the blood of the lizards. This action is not a peculiarity of Texas lizard, other animals such as snakes and some insects can also spray blood (or Emolinfa in the case of insects) to discourage and remove the predators.
The cuckold lizard spraying blood from the eyes to frighten the predators
The evolutionary origin of this behavior is not yet completely Chiara Chiara. When the animal feels at the grip, venous blood is made through the jugular vein of the animal to accumulate in the orbital breastsof the bags present in all reptiles at the eye level, but particularly pronounced in the cuckold. Small specialized muscles then narrow the jugular vein and a strong pressure develops inside the orbital bag. The eyes of the lizard take on a Rigonfio aspect, Sign that is preparing to spray!
Finally, the animal compresses the eye muscles up to breaking the blood vesselsmaking the blood come out strongly from a duct between the eyelids. However, if it is left at peace before the spray and no longer feels in danger, the eyepieces of the lizard deflate.
The effects of the blood jet on predators
The jet, projected by the corners of one of the two eyes, can reach about 1 m away and is not sprayed at random, but directed with precision towards the open faucks of the assaulter. This defensive strategy seems to be directed specifically against only some of the natural predators of these animals, namely Coyote, dogs and foxes. In addition to scary and disorient these canids, the blood of the cuckold seems to contain some kind of repellent which has effect on them but not on other predators such as runner birds.
A study that tested the blood reactions of lizards by Coyote and other canids suggested that the latter find it particularly disgusting When this is sprayed on the nose and mouth. It is not yet clear what the chemical component of their blood is that triggers the olfactory reaction capable of dissuading these predators and if this is taken by the lizard through its diet. The pointed armor of the horned lizard is a further deterrent: if attached, this flattens or directs the horns of the head towards the predator’s mouth, to make itself as palating as possible.
Autoemorrhagia in other animals
The cuckold of Texas lizard is not the only one to use its own blood for self -defense. THE’defensive autoemorrhage It can also be found in some species of snakes when they feel threatened. But unlike the cuckold, it is not a powerful and direct jet, but a slower secretionwhich fills the oral cavity and eye bulbs, making him take a bright red color. In other cases, snakes emit blood from cloacathe rear area from where the waste expels, probably to make their behavior more convincing tanatosis, Another defensive strategy in which the animal pretends to be dead to disorient or discourage a predator.
And even if they do not have “blood” in the same way as the vertebrates, different species of insects, such as meloids, lady of ladybugs or some grasshoppers, are able to expel theirs from the abdomen or joints Emolinfa (the liquid circulating inside them and replies the same functions as the blood). This expulsion is both slow and type explosive and direct And sometimes the emolinfa contains stinging substances for predators that the insect accumulates from plants that ingest with the diet. What the species is, expelling blood is an energetically expensive matter and which risks dehydrating the animal: reason this defense behavior is so rare.
