Here are some examples of different animals reacting differently to given toxins
1. Sydney funnel web venom causes only extremely mild signs in dogs cats mice rabbits etc but is very toxic and potentially lethal in even adult humans. The funnel web possessed a neurotoxin
Spider Envenomation, Funnel Web: eMedicine Emergency Medicine
2. Queensland Tarantula venom causes only very mild symptoms in humans, even in young children[ local pain] yet has a near 100% DEATH rate for dogs and a nearly 50 percent death rate for cats
"There were nine confirmed bites by spiders of the family Theraphosidae in humans and seven in canines. These included bites by two Selenocosmia spp. and by two Phlogiellus spp. The nine spider bites in humans did not cause major effects. Local pain was the commonest effect, with severe pain in four of seven cases where severity of pain was recorded. Puncture marks or bleeding were the next most common effect. In one case the spider had bitten through the patient's fingernail. Mild systemic effects occurred in one of nine cases. There were seven bites in dogs (Phlogellius spp. and Selenocosmia spp.), and in two of these the owner was bitten after the dog. In all seven cases the dog died, and as rapidly as 0.5-2h after the bite. This small series of bites by Australian theraphosid spiders gives an indication of the spectrum of toxicity of these spiders in humans. Bites by these spiders are unlikely to cause major problems in humans. The study also demonstrates that the venom is far more toxic to canines."
Bites by spiders of the family Theraphosidae in hu... [Toxicon. 2003] - PubMed result
3. For Redback spider and Black Widow bites.
“There is considerable species variation in susceptibility to envenomation. The guinea pig, horse and camel are very susceptible while the dog is relatively resistant to the effects of the venom. It is seldom lethal in dogs unless a considerable number of bites are inflicted, as would most likely only occur under experimental conditions. The susceptibility of the cat probably lies between that of guinea pigs and dogs."
"Redback antivenom is not normally required as a life saving measure in dogs, but its use may be considered in cases where redback envenomation is suspected in order to relieve the immediate discomfort or where a pre-existing condition, such as cardiac dysfunction, is present.”
“It is reported that cats, being more susceptible to redback venom, do receive antivenom from veterinarians and respond dramatically in minutes with significant lessening of signs."
Spider Bite | Australian Venom Research Unit
So their u have it many different animals reacting way differently to different individual neurotoxic venom's. The dog is resistant to the neurotoxic venom of the redback and black widow, extremely weak to the neurotoxic venom of the tarantula and highly resistant to the funnel web neurotoxin. The cat is then highly resistant to the funnel web, weak to the redback and the black widow and very weak to tarantula[ through not as weak as the dog]. Humans are weak to the funnel web, very resistant to the tarantula and moderately strong to the funnel web/black widow. Rabbits are very resistant to the funnel web neurotoxin yet they get taken out in the 20's by black mamba neurotoxins and the same goes for dogs[ I have an account where 4 dogs were killed at once by a single black mamba] yet they are resistant to most spider neurotoxins[ except for the tarantula which they are extremely weak to] and they extremely weak to many snake neurotoxins.
And look at this... A single black mamba killed 15 rabbits at one time[ without getting hurt]
Black Mamba | Nature | PBS Video
The scene happens from 00:31:48-00:32:12
So this is another example... Both the black mamba and the funnel web are neurotoxic... but the funnel web barely hurts rabbits at all and a black mamba venom absolutely devastates them... So why is that..? Easy awnser... because ALL animals react differently to different snake venoms.. Their is no uniform level of toxicity for all animals... And the only way to get an acurate reading is to test it on THAT SPECIFIC ANIMALS ie humans... Obviously this will never happen but the mice tests are a sorry excuse for a "toxicity study"