Human beings communicate with animals in myriad ways: verbal commands, hand signals, and the use of punitive instruments like the whip. When "The Day of the Dolphin" was released in 1973, the U.S. Navy's Marine Mammal Training Program had already been in existence for over a decade (and continues to operate from its base in San Diego). When placed in this context, the premise that a bottlenose dolphin could be taught the rudiments of speech does not appear so fantastic.

Screenwriter Buck Henry, in an interview recorded for the 2005 DVD release, offers some justification for his work. Henry disregarded the most implausible elements of Robert Merle's novel, upon which the film is based. In Merle's version, the dolphins speak English fluently enough to discourse on abstract subjects such as God. Henry thought audiences would find this laughable. Henry's concept of animal speech works within the reality of the film even if, as he acknowledges, the plot structure has deficiencies.

What differentiates the mammals from the humans, in this Watergate-era film, is deception. The two dolphins trained by marine biologist Jake Terrell (George C. Scott) are incapable of lying. Terrell, however, keeps his work secret from the foundation that is funding his research. The foundation turns out to be front for a shady governmental group. They, in turn, have infiltrated Terrell's institute by planting a former Navy Seal in the research group. Curtis Mahoney (Paul Sorvino), masquerading as a journalist, is spying on the foundation. The film's portrayal of competing government factions attempting to sabotage one another compares favorably with other paranoid political thrillers of the 1970s (including "Three Days of the Condor" and "The Parallax View").

Actor Edward Hermann, who has a small role as one of Terrell's researchers, was also interviewed for the DVD release. During the three month shoot on an island in the Bahamas, director Mike Nichols's enthusiasm for his subject dimmed. Hermann reports that near the end of principal photography, Nichols was asking him what "The Day of the Dolphin" was about. The filmmaker's lack of focus explains why the assassination sequence in the third act, which should be nail-biting, is instead merely perfunctory. The first half of "The Day of the Dolphin" is superior to the second.

The final scene in the film was the last to be photographed. Buck Henry tells a story that may be Hollywood hyperbole, but I sincerely hope it is true. The scene takes place in open water. The two dolphins, Alpha and Beta, are set free by Terrell. According to Henry, after the first two takes the dolphins dutifully returned to their handlers. On the third take, after Nichols declared a wrap, the dolphins swam out to sea, never to return.

"The Day of the Dolphin" is rated PG and is available on DVD. As of this date, it is not streaming online. I watched "The Day of the Dolphin" at my own expense. Review posted on 2/9/2019.