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Image: Gino J. D’Angelo, et al/ University of Georgia

A Minnesota mushroom hunter happened upon quite a rare find: a stillborn two-headed fawn.

This is a first — before this, the only known case of conjoined fawns had been observed in utero (inside the mother’s womb).

“It’s amazing and extremely rare,” University of Georgia scientist Gino D’Angelo said in a statement. “We can’t even estimate the rarity of this. Of the tens of millions of fawns born annually in the U.S., there are probably abnormalities happening in the wild we don’t even know about.”

What would cause a fawn to develop with two heads? In this case, the specimen was actually a set of female conjoined twins that had failed to separate. A CT scan, MRI, and subsequent necropsy revealed that while they had normal fur, heads and legs, the fawns had fused spines, a shared liver, and two heartsthat shared a single pericardial sac. They had two separate esophagi and forestomachs, but one of them was completely closed off.

“Their anatomy indicates the fawns would never have been viable,” said D’Angelo.

A test on the fawns’ lungs concluded that they had never taken a breath, indicating that they were stillborn. But despite the twins’ death, it appeared that their mother had groomed and cared for them for a period of time.

Conjoined twins are rarely found in the wild and most do not make it to birth. In fact, scientists are still unsure exactly what causes this phenomenon.

“Even in humans we don’t know,” D’Angelo explained. “We think it’s an unnatural splitting of cells during early embryo development.”

For those that want to view the anomaly in person, the fawn will be on display at  Minnesota Department of Natural Resources. The results of the examination were published in the journal The American Midland Naturalist.