Venomous mammals

Abstract

It is not widely appreciated that mammals can be venomous in the manner of snakes and lizards. However, it was first demonstrated scientifically 50 years ago in the case of the American short-tailed shrew. Subsequently, similar evidence has been obtained from European shrews and the Haitian solenodon, but research in this area has been almost completely neglected for the last 20 years. In complete contrast to what has been learned about other animal venoms, the identity and mode of action of mammal venom toxins are still unknown. This review draws attention once more to the pioneering work undertaken in the 1940s and 1950s, exploring in more detail than hitherto why the implications of mammal venom are just as important as the chemistry and pharmacology of the phenomenon itself.

Blarina toxin, a mammalian lethal venom from the short-tailed shrew Blarina brevicauda : Isolation and characterization

“…Products from precipitation of the crude extracts with ammonium sulfate (33-80% saturation) are toxic. Therefore, it has been suggested that the most toxic ingredient is a high molecular weight water-soluble protein, not a carbohydrate or nucleoprotein (1). However, because the Blarina venom loses its toxicity rapidly after the victim's death, its purification and more precise identification have not been successfully completed.…”

“…In general, soricine shrews consume large amounts of food to meet their high metabolic demands (11). Although they belong to the order Insectivora, B. brevicauda do not eat insects and invertebrates exclusively but also vertebrates, even larger than themselves, such as murid rodents and frogs (1,(11)(12)(13). Therefore, this shrew species may use its venom to paralyze and catch larger preys.…”

“…The acute toxicity and proteolytic activity of BLTX were strongly inhibited by aprotinin, a kallikrein inhibitor, suggesting that its toxicity is due to a kallikrein-like activity of the venom. V enomous mammals are rare (1), and their venoms have not been characterized. Toxic constituents produced by other vertebrates, such as snake, lizard, and frog, have been well studied.…”

“…Among mammals, the short-tailed shrew B. brevicauda (Say, 1923) is well known to produce a potent venom in its saliva, which is toxic to mammals, such as mice, voles, rabbits, and cats (1,3). Human accounts of bites from Blarina describe a local burning sensation around the tooth puncture marks and subsequent swelling (10).…”

An investigation of the evolution of the anguimorph lizard venom system

“…The teeth of helodermatid lizards are deeply grooved in a manner convergent with those of some advanced snakes, in which grooved, venom-delivering teeth have independently evolved on multiple occasions and display extensive variation (Russel and Bogert, 1981;, This is also convergent with various other extant and extinct venomous lineages including archosauriforms (Mitchell et al, 2010), conodonts (Szaniawski, 2009), sphenodons (Reyonso, 2005, insectivorous mammals such as shrews and solenodons (Cuenca-Bescos and Rofes, 2007;Dufton, 1992;Ligabue-Braun et al, 2012;Rofes and Cuenca-Bescos, 2009) and bird-like dinosaurs hypothesised to specialise in preying upon early birds (Gong et al, 2010).…”