• Thinkstock
    7 of 11

    6. Black Widow Spiders

    Black widow spiders are somewhat reclusive and non-aggressive, but dogs and cats can be bitten when they walk through a spider web outdoors or accidentally lie down on a spider, Dr. Tegzes notes. Cats are very sensitive to the venom, which is 15 times stronger than a rattlesnake’s. The venom can send extreme pain throughout cats’ bodies and cause muscle rigidity, followed by a loss of muscle tone.

    Insect bites and stings, including spiders, prompted 2,428 claims to VPI pet insurance in 2011, costing an average of $141.23 per pet.

    Location: More abundant in the South, but black widow spiders are found in most of the Western Hemisphere.

    What to do if your pet is bitten: Seek veterinary care.