History: First appearing in the original movie, Spike was found seconds before he hatched and inducted into the group shortly thereafter by Ducky.  Despite his limited intelligence, he made himself an asset to the team in the final confrontation with Sharptooth and was ultimately adopted into Ducky's family.

In the series, Spike is still mostly dim and slow-witted, though he occasionally shows some intelligence – as seen in Meadow of Jumping Waters, when he uses a foul odor to ward off Redclaw and the Fast-Biters.

Personality: The youngest of the original crew, Spike is not exactly the sharpest knife in the drawer. As one might expect from a species so large with brains so small, he seems to spend nearly all his time focused on eating; in fact, when he hatched the first thing he did was eat his own nest! Despite his limited intelligence, Spike is good-natured and good-hearted, and readily follows the others' lead in just about anything.

Despite lagging behind the others in many respects, Spike does have some noteworthy skills. He is quite athletic, and is particularly skilled at games involving “pointy seeds” or pinecones (two of these games appear; one, in The Stone of Cold Fire, resembles bowling, while another seen in the TV series has traits of soccer/football and rugby). He also successfully trains as a tracker in Episode 13: The Lonely Journey. On a few occasions, such as in that same episode, he even shows occasional fits of creativity, suggesting that he may be more intelligent than he seems.

Communication-wise, Spike is distinctive in that he almost never has any actual spoken lines (though he did manage to say Ducky's name in Journey Through the Mists (Land Before Time IV). On all other occasions, he mostly communicates in grunts, mumbles, and other assorted sounds vaguely resembling speech. However, he does seem to be better than the others at imitating animal noises such as sharpteeth and hoppers.

In Through the Eyes of a Spiketail (Episode 25), Spike is presented as being able to hear plants “sing” (perhaps a case of synaesthesia, or one sense being triggered by another – in this case hearing by smell), and as hearing the others speak in garbled mumbles much of the time just as they hear him. The latter, however, conflicts with the fact that he understands them clearly most of the time. Also, he is depicted as disliking adventures in contrast to his usually agreeable nature.

Family: Spike's biological family is unknown, but when he hatched Ducky took to him at once and introduced him to her family as “our new brother” at the end of the movie. This made him the adopted son of Ducky's parents and gave him several siblings of unspecified gender (but female appearance).

Friends: In light of Spike's easygoing nature, it's unsurprising that he tends to have the fewest conflicts with the other members of the group.  In addition to his adoptive bond with Ducky, he is often Littlefoot's first choice for a helping hand (lack of hands notwithstanding).  He has also been seen to fit quite well with Chomper and Ruby, the latter of whom seems to understand him almost as well as Ducky does.

Of his numerous friends, the only one Spike seems to have any significant trouble with is Cera, and even in her case the trouble is very rarely on his end.  Though the others have all, at one time or another, found themselves in trouble because of his ill-timed snack attacks, only Cera ever seems to hold it against him for long.

Out of all the other friends made by the group over the course of the Land Before Time material, Spike has made a few close bonds which particularly stand out.  In Journey Through the Mists (IV), he was the first to make contact with the rodent Tickles, and seemed to enjoy the closest connection with this diminutive friend out of any of the dinosaurs.  He also formed a fast friendship with a younger stegosauus named Tippy in The Big Freeze (VIII), along with Tippy's mother.