What environmental temperature might lead airlines to refuse to ship animals?

Airlines may refuse to ship animals when environmental temperatures fall below 45°F or rise above 85°F because these temperature extremes can compromise the health and safety of the animals during transportation. Animals are often sensitive to temperature changes; they may experience stress or even health crises if exposed to unsuitable conditions for extended periods.

When temperatures are too low, animals can be at risk for hypothermia, particularly those that are smaller or not acclimatized to cold. Conversely, high temperatures can lead to heat stress or heat stroke, which can be life-threatening. Therefore, the threshold established by many airlines is designed to ensure that animals are transported in a safe and humane manner, significantly reducing the risk of injury or distress.

The other options specify temperatures that either fall within the acceptable range or are not as restrictive as the correct choice, making them less applicable to the guidelines followed by airlines for animal shipping.