Dragons on Middle-earth: How did they reproduce?

Question

Dragons first came about from Glaurung the Golden, who is said to have been the first fire-dragon bred by Morgoth in the First Age.

But thereafter there was peace for many years, and no open assault from Angband, for Morgoth perceived now that the Orcs unaided were no match for the Noldor; and he sought in his heart for new counsel.

Again after a hundred years Glaurung, the first of the Urulóki, the fire-drakes of the North, issued from Angband's gates by night. He was yet young and scarce half-grown, for long and slow is the life of the dragons, but the Elves fled before him to Ered Wethrin and Dorthonion in dismay; and he defiled the fields of Ard-galen.

^{_{The Silmarillion - Chapter 13: Of the Return of the Noldor}}

There are many speculations of the origins of Dragons, but this question is not asking that. Glaurung is also known as the 'Father of Dragons', or also the 'Father of the Fire-drakes'. Brood is defined as: "a number of young produced or hatched at one time; a family of offspring or young." That would mean that all of the Dragons were descended from Glaurung.

In the front of that fire came Glaurung the golden, father of dragons, in his full might; and in his train were Balrogs, and behind them came the black armies of the Orcs in multitudes such as the Noldor had never before seen or imagined.

^{_{The Silmarillion - Chapter 18: Of the Ruin of Beleriand and the Fall of Fingolfin}}

And but for them Glaurung and his brood would have withered all that was left of the Noldor.

^{_{The Silmarillion - Chapter 20: Of the Fifth Battle: Nirnaeth Arnoediad}}

At last, in the year when Eärendil was seven years old, Morgoth was ready, and he loosed upon Gondolin his Balrogs, and his Orcs, and his wolves; and with them came dragons of the brood of Glaurung, and they were become now many and terrible.

^{_{The Silmarillion - Chapter 23: Of Tuor and the Fall of Gondolin}}

But how-? How did Glaurang reproduce, and subsequently all the Dragons after him? Was it stated anywhere that it was done so asexually or sexually, or through an experiment of Morgoth?

Answer 1

We have two things to suggest that dragons bred.

• We are told that they bred before they began to war with the Dwarves. This occurs at the Withered Heath.
• The second is that there are a couple of mentions of Dragonets, which seem to be baby Dragons.

The breeding of said Dragons more than likely occurred sexually as opposed to asexually as in the years of Tolkien's writings, asexual behaviour was less spoken of, in Humans. I use Humans as the basis as I was unable to find a date for when asexuality in animals was first observed or researched. However, the title "Father of Dragons" need not be literal and my simply mean that he was the first, or the fiercest.

In addition to the point made by Drakewise Banshee, about evidence of Dragons "breeding" at the Withered Heath.

In the Unfinished Tales Chapter Quest for Erebor Glóin discusses his opinion of including a Hobbit in their quest by discussing what he calls "Dragonet"s.

“What!” cried Glóin. “One of those simpletons down in the Shire? What use on earth, or under it, could he possibly be? Let him smell as he may, he would never dare to come within smelling distance of the nakedest dragonet new from the shell!
_{Unfinished Tales: Part Three: The Third Age - Chapter 3, The Quest of Erebor}

This seems to suggest to us that Tolkien had thought about female Dragons laying eggs. In a similar way most reptiles would. This would also explain the multiplying of Dragons before they begun to "make war" on the Dwarves.

But there were dragons in the wastes beyond: and after many years they became strong again and multiplied, and they made war on the Dwarves, and plundered their works
_{Return of the King: Appendix A}

There is one more mention of Dragonets in Tolkien's legendarium. This is in the Fellowship of the Ring when Frodo is described as a dragonet reaching down into the stream to drink water.

Half in a dream he wandered forward to the riverward side of the tree, where great winding roots grew out into the stream, like gnarled dragonets straining down to drink.
_{Fellowship of the Ring - Book 1: Chapter 6, The Old Forest}

To go on. There is another mention of dragons breeding. The first being the aforementioned breeding mentioned in the Hobbit.

And I know where Mirkwood is, and the Withered Heath where the great dragons bred.
_{The Hobbit: Chapter 1, An Unexpected Party}

Likely the only truly canonical source for said breeding. However it is mentioned in The Shaping of Middle-earth (Volume 4 of the History of Middle-earth)

“ For a while his Orcs and Dragons breeding again in dark places troubled and affrighted the world”
_{The Shaping of Middle-earth}

Answer 2

The earliest 'drakes' in the Fall of Gondolin were mechanical, and did not reproduce at all:

the heats of those drakes lasted not for ever, and might only be plenished from the wells of fire that Melko had made in the fastness of his own land.

The Fall of Gondolin, HoME II

As for dragons in later writings (Glaurung, Ancalagon, Scatha, Smaug^*), the answer is 'we don't know for sure, but we have a damn good guess' that it was sexual reproduction:

"I don't see that this will help us much," said Thorin disappointedly after a glance. "I remember the Mountain well enough and the lands about it. And I know where Mirkwood is, and the Withered Heath where the great dragons bred."

The Hobbit, Chapter I

It is quite possible, in Tolkien's universe, for a long-lived being to be unable to find a mate for reproductive purposes - see the Ents and the Entwives. While the fate of the Entwives is unknown, it is not unthinkable that female dragons (dragonettes?) could have fallen prey to greed/envy/ennui of their mates. One may not discount an idea of mantis-like behavior among dragons.

¹_{All the names are male (including Scatha), but it doesn't prove anything. Tolkien wrote about the female of the species when she was noteworthy (Shelob) or exceptionally beautiful. She-dragons might have been neither.}