Which of the following is a sign of toxicity from Bufo marinus/Rhinella marina?

Pawing at the mouth is a sign of toxicity from Bufo marinus, commonly known as the cane toad. This species secretes potent toxins in its skin, which can cause a range of symptoms in animals, particularly in pets such as dogs that may encounter them. When a dog is poisoned by the toxins, they may exhibit signs of distress, including pawing at their mouths in an attempt to alleviate the discomfort caused by the toxic substance.

The severity of the reaction can vary depending on the amount of toxin absorbed and the size of the animal, but this pawing behavior is typically a direct response to the irritation and discomfort they are experiencing. Recognizing this sign is crucial for timely veterinary intervention to prevent further complications from the toxin.

Other options listed, such as excessive barking, weight gain, and increased thirst, are not typical signs associated with Bufo marinus toxicity. Instead, they may correlate with other health issues that are unrelated to the direct effects of the toxins from this specific species.