False. Not ALL mammals have nipples. Male horses, most male rodents, but the biggest example is the platypus. The female platypus lays eggs instead of giving live birth and does not have nipples but rather secretes milk from pores to feed their young.
Thank you for your interest
True...however, the Oxford dictionary definition specifies only 3 criteria: "hair/fur, produces milk, & (typically) give birth to live young". Since 'typically' suggests that some atypical situations are possible, a coconut can fall within this definition. I don't mean to be argumentative, but...while homeothermic is a common trait of mammals it is not, by definition, a defining characteristic.
