Why are there no poisonous mammals?

Question

This planet has poisonous reptiles, insects, fish, etc, but no poisonous mammals. Why??

Answer 1

mammels had other means to survive and took an evolutional step away from poison and venoms a long, long time ago.

Answer 2

Poisonous Mammals List

Answer 3

The platypus has poison sacks near its hind legs, but it is a monotream.

The development of poison and venom has taken place for different purposes on only a few occasions (a very small number of all creatures that have ever lived have done so). Mammals and birds probably did not evolve from a reptile that had the ability to produce poison. It stands to reason that if there are other less costly ways for creatures to capture prey or to escape danger (like having a large brain, developing potent toxins takes a lot of energy), then they would be selected for by the evolutionary process.

Answer 4

Actually there are some poisonous mammals. The male platypus has a poisonous spur on both of its hind leg for self-defense and battling for a mate. Also, the slow lorris (kind of like a sloth) has poisonous saliva that it coats its baby with for protection from predators.

Granted, the difference between what is poisonous and what is venemous is relative. Venom generally makes something really sick, by poison can kill. Just because it's only venemous to humans, doesn't mean it isn't poisonous to its predators and others of the same species.

Answer 5

Only about 4 poisonous mammals

Duck billed platypus--The males have a sharp, hollow spur on each back foot. Poison can flow through these spurs and into a stabbed enemy.

The short-tailed shrew of North America, have poisonous saliva. When one of these shrews bites, the poison paralyzes its prey.
There are 2 species of shrew (blarina and neomys species) , which have a special substance (a neurotoxin) in their saliva that can slow down their prey.

The rare terrestrial solenodon is a slow-moving, nocturnal animal that feeds on ants, other insects, grubs, small reptiles, fruit and other plant matter, for which it roots about on the ground, through forest litter, and ripping open rotten logs. Its elongated cartilaginous snout and scent glands in the armpits and groin suggest that smell is the solenodon's predominant sense. The solenodon has poisonous salivary glands with ducts opening at the base of its large second lower incisors, which are deeply grooved on the inner sides to inject venom when biting.


Mammals typically have other features for protection (instead of poison/venom), especially a well developed brain. SO they do not have as "primitive" modes of protection, i.e. poison.

Answer 6

the answer is duck-billed platypus which is venomous not poisonous which is none.The male platypus has venomous ankle spurs which produce a cocktail of venom, composed largely of defensin-like proteins or DLPs, which are unique to the platypus. The venom is not lethal to humans but will produce excruciating pain — so intense that the victim may be incapacitated. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from case histories and anecdotal evidence indicates that the pain develops into a long-lasting hyperalgesia that persists for days or even months. The venom can be lethal to small animals.Venom is produced in the crural glands of the male, which are kidney-shaped alveolar glands connected by a thin-walled duct to the spur, and is inflicted through a calcaneus spur on each hind limb. Females, like echidnas, have rudimentary spur buds which do not develop and do not have functional crural glands.

Calcaneous spurThe venom appears to have a different function from venoms produced by non-mammalian species, its effects are non-life threatening but nevertheless may seriously impair the victim. Since only males produce venom and the production rises during the breeding season it is theorized that it is used as an offensive weapon to assert dominance during this period.

Answer 7

I would like to clarify something for you..... Poisonous is not the same as Venomous.... In normal usage, a poisonous organism is one that is harmful to consume, but a venomous organism uses poison to defend itself while still alive. A single organism can be both venomous and poisonous.

Today very few mammals are venomous. The male platypus has a hollow foot spur attached to a venom sac. The only other venomous mammals are four species of shrew and the two species of solenodon which have venomous saliva, and the slow loris which has poison glands on its arms.

There are, however, suggestions that venomous mammals were once more common. Teeth dated at 60 million years old from two extinct species, the shrew-like Bisonalveus browni and another unidentified mammal, show grooves indicative of a venomous bite. It has also been suggested by Mark Dufton of the University of Strathclyde that modern animals do not need venom because they are smart and effective enough to kill quickly with tooth or claw; whereas venom, no matter how sophisticated, takes time to disable prey. Indeed, the venomous insectivore, the solenodon, is now being driven from its native habitats by introduced dogs, cats, and mongooses.

Venomous mammals of today

Cuban Solenodon (Atopogale cubana) & Haitian Solenodon (Solenodon paradoxus)
Solenodons look similar to big hedgehogs with no coat of spines. They both have venomous bites; the venom is delivered from modified salivary glands via grooves in their second lower incisors.
Platypus (Ornithorhyncus anatinus)
Males have a venomous spur on their hind legs. Echidnas, the other monotremes, have spurs but no functional venom glands.
Eurasian water shrew (Neomys fodiens)
Capable of delivering a venomous bite.
Northern Short-tailed Shrew (Blarina brevicauda)
Capable of delivering a venomous bite.
Southern Short-tailed Shrew (Blarina carolinensis) & Elliot's Short-tailed Shrew (Blarina hylophaga)
Possibly have a venomous bite.

Venomous/poisonous
Slow loris (Nycticebus coucang)
Glands on the inside of their elbows secrete a toxin that smells like sweaty socks. They cover their babies in the toxin to protect them from predators, and put it in their mouths to give themselves a venomous bite, delivering the toxin via their lower incisors.

There are no species of venomous bird, however some birds are poisonous to eat or touch, such as the pitohui.

Answer 8

There are venomous mammals. The list of known venomous mammals are as follows: lorises, short-tailed shrews, Eurasian water shrews, solenodons, shrews, and platypuses. Hedgehogs have been known to kill toads and smear the poison glands on their spines.

Added bonus: The world's only known venomous birds are found in New Guinea. There are 3. The hooded pitohui, Variable Pitohui, and the Brown Pitohui have venomous saliva and skin. They were discovered in 1995 as being venomous.

Answer 9

Humans are mammals and we're doing a good job of poisoning the planet.

Seriously, mammals tend to have other weapons like teeth and claws to defend / attack with.

Answer 10

Ooops. There are.

The egg-laying platypus of Australia is the world's most poisonous mammal. Males have hollow spurs connected to venom glands on the ankle of each hind leg. The extremely painful poison can harm a man but won't kill him.

Answer 11

Because mammals have other ways of defending themselves, like teeth and claws whereas insects & reptiles are too small or weak, so their only option is poison.