Acidic marine conditions brought on by climate change could corrode the teeth of blacktip reef sharks (Carcharhinus melanopterus). One half of each set went into a control tank, mimicking an ocean pH of 8.1. Those kept in the more acidic water were significantly more corroded, and had far more cracks and holes, especially at the root and tooth base. While sharks do replace their teeth continually, the findings suggest that they would need to do so more frequently in the more acidic oceans caused by climate change. Port Jackson sharks’ teeth are less exposed to the ambient water than those of blacktip reef sharks, and have a different anatomy.