I'm not so great when it comes to love and stuff, but I'm still hoping I can honor the spirit of Valentine's day in my own right. So I've created a collage of various Mesozoic-era animals during the mating season in the spirit of Valentine's Day. I don't have premium membership, but feel free to critique if you'd like.
A male Therizinosaurus in the middle of constructing a bower, which attracts the attention of a female. Some modern birds, most notably the bowerbirds, create decorative nests to attract females with a stable home suitable for raising offspring. I figured that therizinosaurs could do the same, using their long claws and powerful arms to bend tree branches towards each other and tangle them into an arch as a base for a bower, then decorating it with colorful objects like fruits and flowers, even any bones they may come across. Claw markings in the bark of nearby trees would also mark its presence, as modern bears do.
A male Majungasaurus using its clamp-like jaws to hold onto a female during copulation. Abelisaurids have very short arms like tyrannosaurids, but to a more vestigial degree. Tyrannosaurid arms are at least capable of limited grasping, which is currently believed to aid in gripping when a male mounts a receptive female. This had me thinking how abelisaurids pulled it off when their arms were virtually functionless. Then I remembered that Majungasaurus jaws and teeth were built for gripping and subduing prey, so why can’t a male do the same to subdue a female to copulate with her? As well as to keep from slipping and falling away in the middle of the process? Perhaps the male may have also bitten the female to show interest, explaining a possible function for thick, bumpy skin in abelisaurids (as seen in skin impressions from Carnotaurus). Such behaviors are known in modern sharks. On a side note, with the evidence of cannibalism in Majungasaurus, I’ve speculated that the female may have eaten the male after copulation to provide nutrients for herself and her developing eggs, as other resources may have been at times scarce on such a small island ecosystem as Late Cretaceous Madagascar. Such behavior is known in modern spiders and mantises.
A pair of Nyctosaurus locked together in courtship flight, as well as copulation. Having lost all its fingers except for the wing finger, ground movement would have been especially impaired for this species, which had me questioning its copulation method. So I came up with this idea: each partner flies in an upward circle or arch, reaching out with their legs and grasping each other at the lower body when in reach, bringing their cloacas in proximity to permit copulation that only requires a short time before needing to break away. This idea is inspired by the courtship rituals in modern bald eagles.
A pair of Elasmosaurus locked together in aquatic copulation. Modern dolphins use their pectoral flippers to hold themselves in position. In plesiosauroids, I suppose their pelvic flippers served this role, leaving the pectoral flippers free for any necessary movement or balance. With the Elasmosaurus, I took the liberty of depicting a corkscrew-like ritual during copulation, mostly for artistic effect, although it’s not implausible behavior. Perhaps this maneuvering would aid in maintaining position.
A male Saichania attracting a female by performing a courtship dance. A study showed that the plates and spikes in ankylosaurids and polacanthids are less sturdy compared to small, minor osteoderms, and instead may have been more functional in thermoregulation and display. With some similarities in armor between ankylosaurs and crocodilians, I figured that male ankylosaurs could send infrasound through their bodies, causing them to vibrate and thus making their armor shake in a display attractive to females, and perhaps vice versa. Another study showed that tail clubs continued to grow in adult ankylosaurs, indicating that they also had a social role in addition to a defense role, so I depicted the Saichania showing off his tail as part of his display. I’ve also noticed that Ankylosaurus, the last of the ankylosaurids, had very prominent head spikes compared to earlier ankylosaurids, so I speculate that head spikes also had a display function in mating (though I’m probably not the first). Scientists have also speculated that the complex nasal passageways in ankylosaurs may have been capable of resonating sound, like in the crests of Parasaurolophus and other lambeosaurines. So I’ve tried to depict this hypothesis in the male Saichania, although looking back, I guess trying to hoot/honk while simultaneously vibrating the body with infrasaound might not actually be possible. Oops.
A male Masiakasaurus offering a fish to a female. This idea is inspired by courtship behavior in certain modern birds such as kingfishers, in which a male attempts to feed a small fish headfirst to a female to initiate mating, which I presumably is meant to convey that he is a fit, resourceful mate that will ensure the success and protection of their offspring.