Editing Diplodocidae (section)

==Paleobiology==
===Diet and feeding===
Their teeth were only present in the front of the mouth, and looked like pencils or pegs. They probably used their teeth to crop off food, without chewing, and relied on [[gastrolith]]s (gizzard stones) to break down tough [[plant]] fibers (similar to modern [[bird]]s).
Diplodocines have highly unusual teeth compared to other sauropods. The crowns are long and slender, and elliptical in cross-section, while the apex forms a blunt, triangular point.<ref name="Upchurch2000"/> The most prominent wear facet is on the apex, though unlike all other wear patterns observed within sauropods, diplodocine wear patterns are on the labial (cheek) side of both the upper and lower teeth.<ref name="Upchurch2000"/> 
[[File:Seismosaurus skull.jpg|left|thumb|Seismosaurus (=Diplodocus)]]
This implies that the feeding mechanism of ''Diplodocus'' and other diplodocids was radically different from that of other sauropods. Unilateral branch stripping is the most likely feeding behavior of ''Diplodocus'',<ref name="Norman1985"/><ref name="Dodson1990"/><ref name="BarrettUpchurch1994"/> as it explains the unusual wear patterns of the teeth (coming from tooth–food contact). In unilateral branch stripping, one tooth row would have been used to strip foliage from the stem, while the other would act as a guide and stabilizer. With the elongated preorbital (in front of the eyes) region of the skull, longer portions of stems could be stripped in a single action.<ref name="Upchurch2000"/> Also, the palinal (backwards) motion of the lower jaws could have contributed two significant roles to feeding behaviour: 1) an increased gape, and 2) allowed fine adjustments of the relative positions of the tooth rows, creating a smooth stripping action.<ref name="Upchurch2000"/>

Young ''et al.'' (2012) used biomechanical modelling to examine the performance of the diplodocine skull. It was concluded that the proposal that its dentition was used for bark-stripping was not supported by the data, which showed that under that scenario, the skull and teeth would undergo extreme stresses. The hypotheses of branch-stripping and/or precision biting were both shown to be biomechanically plausible feeding behaviors.<ref name="Young2012"/> Diplodocine teeth were also continually replaced throughout their lives, usually in less than 35 days, as was discovered by Michael D'Emic ''et al.'' Within each tooth socket, as many as five replacement teeth were developing to replace the next one. Studies of the teeth also reveal that it preferred different vegetation from the other sauropods of the Morrison, such as ''Camarasaurus''. This may have better allowed the various species of sauropods to exist without competition.<ref name="D'Emic2013"/>

===Growth===
Long-bone histology enables researchers to estimate the age that a specific individual reached. A study by Griebeler et al. (2013) examined long bone histological data and concluded that the diplodocid MfN.R.2625 weighed {{Convert|4753|kg|ST|1|abbr=off}}, reached sexual maturity at 23 years and died at age 24. The same growth model indicated that the diplodocid MfN.R.NW4 weighed {{Convert|18463|kg|ST|1|abbr=off}}, and died at age 23, before reaching sexual maturity.<ref name="Griebler2013"/>

===Paleopathology=== 
An unnamed diplodocid specimen from the [[Morrison Formation]] nicknamed "Dolly" shows evidence of a throat infection that created cauliflowered bone in the vertebral air sacs. The infection is theorized to have been similar to [[aspergillosis]], though research is ongoing. Whether or not the infection contributed to the dinosaur's death remains unknown.<ref>{{Cite web|url=https://www.livescience.com/dinosaur-respiratory-infection-first-evidence-sauropod|title = Achoo! Respiratory illness gave young 'Dolly' the dinosaur flu-like symptoms|website = [[Live Science]]|date = 10 February 2022}}</ref><ref>{{Cite web|url=https://www.cnn.com/2022/02/10/world/dinosaur-respiratory-infection-scn/index.html|title = Discovery of what ailed Dolly the dinosaur is a first, researchers say|website = [[CNN]]|date = 10 February 2022}}</ref>

===Tail function===

Diplodocids also had long, whip-like [[tail]]s, which were thick at the base and tapered off to be very thin at the end. Computer simulations have shown that the diplodocids could have easily snapped their tails, like a [[bullwhip]]. This could generate a [[sonic boom]] in excess of 200 [[decibel]]s, and may have been used in mating displays, or to drive off predators. There is some circumstantial evidence supporting this as well: a number of diplodocids have been found with fused or damaged tail [[vertebra]]e, which may be a symptom of cracking their tails: these are particularly common between the 18th and the 25th caudal vertebra, a region the authors consider a transitional zone between the stiff muscular base and the flexible whiplike section.<ref name="MyrhvoldCurrie1997"/> However, Rega (2012) notes that ''[[Camarasaurus]]'', while lacking a tailwhip, displays a similar level of caudal co-ossification, and that ''[[Mamenchisaurus]]'', while having the same pattern of vertebral metrics, lacks a tailwhip and doesn't display fusion in any "transitional region". Also, the crush fractures which would be expected if the tail was used as a whip have never been found in diplodocids.<ref name="Rega2012"/> More recently, Baron (2020) considers the use of the tail as a bullwhip unlikely because of the potentially catastrophic muscle and skeletal damage such speeds could cause on the large and heavy tail. Instead, he proposes that the tails might have been used as a tactile organ to keep in touch with the individuals behind and on the sides in a group while migrating, which could have augmented cohesion and allowed communication among individuals while limiting more energetically demanding activities like stopping to search for dispersed individuals, turning to visually check on individuals behind, or communicating vocally.<ref name="Baron2021"/>