Red blood cells, or erythrocytes (erythro– = “red”; –cyte = “cell”), are specialized cells that circulate through the body delivering oxygen to cells; they are formed from stem cells in the bone marrow.

The “camels have nucleated RBCs” story is just another stubborn myth. Red blood cells do not have a nucleus. They have a nucleus because they don't need much oxygen.

YES.

Immature red blood cells actually do have a nucleus but when they differentiate to become the mature red blood cells the nucleus is actually ejected, so they have no nucleus and no DNA. Red blood cells, or erythrocytes (erythro being Greek for ‘red’ and cyte meaning ‘cells’) are actually anucleated cells, meaning that they don’t have a nucleus.

Red blood cells are the only cells in the human body that do not have a nucleus. Humans don't have a nucleus in their red blood cells because they need more oxygen than frogs, so our red blood cells eliminated the nucleus to fit more oxygen in. No control or maintenance tasks are done by the cell because would require them to use the oxygen they carry there by defeating their purpose.

As to why this is and how they function, I think the answer is really lies in what they do. Frogs can breathe under water and in air, so they don't need much oxygen, so their red blood cells didn't eliminate the nucleus.

But wait!

Red Blood Cells. Rbc's are derived from haematopoietic stem cells in bone marrow.

While the red blood cells of such animals as fish and birds have inactive nuclei, erythrocytes in humans and a number of other animals do not have nuclei or a nucleus. Red blood cells of birds have nucleus and thus DNA.

Red blood cells, their only real job is to carry oxygen around the body. In mammals, red blood cells are small biconcave cells that at maturity do not contain a nucleus or mitochondria and are only 7–8 µm in size.

This allows the cells to contain more hemoglobin that is … Red Blood Cells do not have a Nucleus.

Red blood cells do not have a nucleus while cheek cells have a nucleus. In humans, when developing in bone marrow have a nucleus and then genomic DNA .

Don’t go away just yet because this is actually a much more tricky question than you would expect.