Milk comes from mammals. This is somehow a remarkable mammal. Our government knows that too. Nevertheless, Chinese scientists have documented jumps that give their young people drops of nutrients from the scar on their mother's body. This is the only diet for spiderlings until they begin to feed, and then they still drink until they become a little more mature. The results are published in Science.
The scissors and pigeons give their young people a substance that is described as "milk" because it comes from their bodies and provides exclusively source of survival for young people. Small cockroaches mother keep this substance in a bag with a stem where their embryos develop.
Dove-mothers and fathers create a milk yield and feed it to baby birds in the first few days of their life until babies read the right food. Vegetable milk consists of cells filled with nutrients that are cut into flakes from the inside of parental bird crops that are under their neck.
Toxeus magnus there are bumping spiders here and look like ants. Their method of caring for children seems different from the two above examples. They have a specialized organ that makes the milk proposed by researchers from uninterrupted eggs that turn into food for the surviving survivors.
These spiders also live in small nuclear family nests where mothers take care of their children even after their maturity. For a while, young people turn to feed, but they still come home, making them even more like mammals.
So this is certainly not a lactation, but these researchers think that they "function and behave in breastfeeding." It also serves a similar evolutionary need: compensate for insecure access to food and keep young people in the nest as long as possible to protect them from predators.
Jumping of spider milk has a protein content of 123.9 mg / ml, four times greater than cow's milk. Vegan is not.
Science, 2018. DOI: 10.1126 / science.aat3692 (O DOI).