It's #LearnAboutButterfliesDay 🦋 While in their larval stage or caterpillar form, the monarch butterfly feeds on plant species in the milkweed family – a group of plants also known to produce substances like cardiac glycosides, which is a toxic compound that many higher animals find distasteful or can be poisonous. These toxins help keep monarch invertebrates safe by providing them with a poisonous defense against predators such as lizards, birds, and frogs! | Wild Kratts