Septic Bite

[Supercommunist]

I realize that the myth that komodo dragon's kill their prey through bacterial infection has been debunked but is possible for an animal to evolve an actual septic bite? And if so how effective of a weapon would it be and what adaptations would the animal need to evolve to develop it.

[Deleted]

Not very effective. Too unreliable.

It's too much of a gamble to depend on, as well as taking way too long. The prey's immune system may fight it off, or it may not.

Also, what if the predator gets a damaged gum and/or mouth membranes? It's not gonna go well...

[Ceratodromeus]

Lots of predatory animals carry bacteria in their mouths that can cause infection if a prey animal escapes, now for the question of if a species would evolve to specialize in this type of prey aquisition, i would doubt it.

[Infinity Blade]

For whatever it's worth, Ceph found this and posted it on Carnivora. Something like a "septic bite" actually seems to have evolved in, surprise surprise, humans.

The Fatal Fang: did stress-induced Xerostomia evolve as a
strategic offensive/defensive weapon in hominid combat?

Sunkavally Satyendra and Lalitha Pappu
1Department of Mechanical Engineering, V.R. Siddhartha Engineering College, Vijayawada, A.P, India
2Department of Microbiology and Food Science and Technology, Institute of Science, GITAM University,
Rushikonda, Visakhapatnam-530045, .P. India.
*Corresponding author Email [e-mail]

The lack of the traditional natural weapons of combat-horn, claw, extended canine, talon, venom etc. has forced the human species to develop a rather novel and unorthodox biological weapon, namely stress-induced xerostomia, or a reduction in salivary flow into the oropharyngial cavity, during those times of psychological stress that are the usual prelude to combat. Since one of the immunologic functions of the saliva is to keep down the number of micro-organisms in the oral cavity, this reduction of salivation immediately results in a marked increase in the bacterial population of the mouth. Since bites are frequently inflicted in combat between humans, this would result in the inoculation of a substantial bolus of pathogenic micro-organism into the bite wound of the opponent, the subsequent setting up of an infective nidus at the bite site, and thus either in fever/sickness or a severe festering wound necessitating, not infrequently, in a need for frank amputation of the affected digit. In any event the combat ability of the opponent will be substantially reduced as a result. It is therefore likely that there has been a substantial Darwinian selection for this peculiar physiologic trait of a desiccation of the mouth during times of inter-personal stress, when the likelihood of there being a physical conflict between humans rises substantially.

Satyendra, Sunkavally, and Lalitha Pappu. "The Fatal Fang: did stress-induced Xerostomia evolve as a strategic offensive/defensive weapon in hominid combat?." Int. J. of Life Sciences 3.3 (2015): 191-199.
files.cluster2.hostgator.co.in/hostgator84521/file/1.sunkavallyandlalitha2015.pdf

However, I'm still not sure if a predator would evolve something like this.

[spartan]

Did I miss something? The paper still talks about bacteria in the saliva playing a pivotal role in the Komodo dragon's hunting strategy.

[Ceratodromeus]

Venom in the komodo dragon is not universally agreed upon.
You can read an argument against venom in this species, as well as other varanids, in this article
www.researchgate.net/profile/Samuel_Sweet2/publication/307612937_Chasing_Flamingos_Toxicofera_and_the_Misinterpretation_of_Venom_in_Varanid_Lizards/links/57cee09e08ae582e0693853f.pdf

[Infinity Blade]

Huh. All this time I thought that venom in varanids was a clear cut issue.

Obviously though, even if venom is not used by Komodo dragons in predation, it doesn't mean that bacterial saliva is (in fact, the paper says that we humans have such a bacteria-ridden bite because we reduce our salivation when under stress).

[spartan]

Just found this, although not directly relevant to this thread I think it may be interesting to some:

pubs.acs.org/doi/abs/10.1021/acs.jproteome.6b00857

Introduction.
The Komodo dragon ( Varanus komodoensis ) is the largest living lizard and inhabits five small islands in southeast Indonesia. These large, carnivorous lizards dominate their ecosystem, hunting invertebrates, birds, and mammals. Although Komodo dragons will ambush and kill their prey directly, they will also feed on carrion or carcasses killed by other dragons and animals. In addition to direct physical attack, bac teria or venom within the dragons’ bite could contribute to the ultimate demise of its prey. In a study analyzing the saliva and oral cavities of multiple dragons in the wild, 57 species of bacteri a were identified, with over 90 percent being classified as potentially pathogenic. The ability of Komodo dragons to endure numerous s trains of pathogenic bacteria in their saliva, yet show no signs of infection, and furthermore recover from wounds inflicted by other dragons reflect the inherent advantage of their innate immune defense and demands further investigation. Moreover, Komodo dragon serum has been demonstrated to have in vitro antibacterial properties against both Gram:negativ e and Gram: positive bacteria.

[Infinity Blade]

Do you have full access to the paper?

That's really interesting, though. That the "bacterial bite" of Komodo dragons may not actually be so much of a myth after all. A bit to take in, lol.

[Ceratodromeus]

I posted that info in the profile, the article doesn't appear to be open access right now.

[spartan]

Feb 25, 2017 10:31:40 GMT 5 Infinity Blade said:

Do you have full access to the paper?

That's really interesting, though. That the "bacterial bite" of Komodo dragons may not actually be so much of a myth after all. A bit to take in, lol.

Yes, one would think it would be rather easy to figure out whether the Komodo dragon uses venom or bacteria (or both), but apparently it's indeed a debated topic as Cerato said.

[Infinity Blade]

Large carnivores of the Pleistocene preyed on proboscideans, the largest of the herbivores (figure 5). Because proboscideans produce offspring at a very low rate, any consistent predation pressure may have limited their populations. For example, mammoth weaning could have been a lengthy process, thus slowing the reproductive rate such that predation at any level may have had serious effects (Rountrey et al. 2007). Using a model, Brook and Johnson (2006) demonstrated that remarkably low levels of juvenile exploitation could have driven Pleistocene megafauna in Australia to extinction as a result of their “slow” life histories. Similarly, Carbyn and colleagues (1993) found that gray wolves in Wood Buffalo National Park, Canada, were able to drive a modern bison population to low levels by preying primarily on bison calves. Carbyn and colleagues (1993) also described how bison could die from blood poisoning as a result of simple puncture wounds infected by bacteria on wolves' teeth.

academic.oup.com/bioscience/article/60/7/516/234159

[Infinity Blade]

Here's an interesting publication about animal bite infections titled "Animal bite-associated infections: microbiology and treatment". The Sci-Hub link to the full paper is down below. In case that particular link no longer works in the future I'll also post the link to the paper down below (that way one can copy and paste the DOI into another Sci-Hub domain).

www.tandfonline.com/doi/abs/10.1586/eri.10.162

sci-hub.do/10.1586/eri.10.162#

Some interesting tidbits I gathered:

• Human bites tend to have a higher rate of complication and infection than the bites of other animals, with ~10-15% of human bites becoming infected.
• Up to 10% of rodent bites can become infected.
• Pig bites have a high incidence of infection.
• Crocodylian bites also not only have a high risk of infection, but the mouth flora might actually be the fecal flora from previous prey.

[creature386]

Dec 28, 2020 0:13:38 GMT 5 Infinity Blade said:

• Human bites tend to have a higher rate of complication and infection than the bites of other animals, with ~10-15% of human bites becoming infected.
• Up to 10% of rodent bites can become infected.
• Pig bites have a high incidence of infection.
• Crocodylian bites also not only have a high risk of infection, but the mouth flora might actually be the fecal flora from previous prey.

At first, I found this fascinating considering how we're the only ones on this list to regularly brush our teeth.

Reading the paper, I realized they were mostly talking about standard infectious diseases like HIV or Hepatitis B. Kinda makes sense that human bites are more infectious than average; we're more likely to transmit human-adapted microbes after all.

Fascinating comparison either way.

[Infinity Blade]

Since 2008, we have observed several tapirs injured by jaguars; most of these tapirs were adults and had a low body condition (Pérez-Flores unpub. data). The health status and weight (between 100 to 120 kg) of these tapirs influence the decision of jaguars to attack them. Tapirs are able to escape from jaguars because they have a large muscle mass, thick and hard skin around their neck, which is where big cats usually grab and kill their prey (Medici 2010). Unfortunately, some injured tapirs die of septicaemia a few days later as a result of the bacteria present in the mouth and claws of jaguars (Pérez-Flores pers. obs.). There are about 200 species of bacteria present in the oral cavity of domestic cats (Felis catus); some of them are highly pathogenic (Dewhirst et al. 2015), so there could be many more in wild felids due to their feeding habits (eat prey and scavenging). For these reasons, we suggest that when Baird’s tapir remains are found in jaguars’ scats, it is most likely from eating carrion or preying on a calf or a juvenile tapir as in this case.

neotropical.pensoft.net/article/57029/