Mating Humans In Bed Videos
Oleta Blaylock
Is motor mirroring in chimpanzees flexible enough to induce yawns in response to species different from themselves? And would chimpanzees distinguish between known and unknown individuals from other species? Captive-reared chimpanzees interact daily with humans, so we wanted to know whether chimpanzees would express an empathic connection with humans in CY. However, chimpanzees may respond to known and unknown humans differently. The research and animal care staff at the Yerkes National Primate Research Center Field Station use positive reinforcement when working with the chimpanzees. Hence, the chimpanzees have an established history of positive interactions with these specific individuals. Potentially, known humans may be categorized as something approaching an ingroup and unknown humans as something approaching an outgroup, with the latter potentially limiting the strength of a contagious response.
To control for species familiarity, we also showed chimpanzees yawns from gelada baboons, a species they have never seen before. Videos of gelada baboons yawning were available from a previous study by Palagi et al. [15]. Comparing the response to humans and gelada baboons allowed us to test whether a familiar, meaningful species is necessary for cross-species contagion, or whether cross-species contagion could be elicited via similarities in motor muscle activation alone.
The new stimuli consisted of three classes of yawn and control videos: familiar humans, unfamiliar humans and gelada baboons (T. gelada). The familiar humans consisted of researchers or husbandry staff who had worked with the chimpanzees for at least 1 year prior to the start of the experiment. The unfamiliar humans comprised individuals who had never been to the Yerkes Field Station before. Gelada baboons were housed at the NaturZoo (Rheine, Germany; see [15] for husbandry details).
For the human videos, we dressed all individuals in a white shirt and placed them in front of a neutral-coloured wall, to minimize potential distracters. The only difference between each video was the identity of the person. The volunteers acted out several yawns, with several seconds between each one. We recorded yawns from seven individuals in each class (familiar to the chimpanzees and unfamiliar) with a PV-GS500 (Panasonic) digital video camera. For the gelada baboons, we reviewed the videos recorded by Palagi et al. [15] and selected yawns from seven individuals. We edited each yawn clip to 9 s using iMovie (Apple). From the same videos of humans and gelada baboons, we selected 9 s control segments from each of the same individuals at rest, performing no expression. By using the same videos, the control clips are virtually identical to the yawn clips, except for the expression itself. We used this control previously [13], and the effect sizes were even larger than when we used open mouth movements as a control [37]. Massen et al. [38] also used this control and found a significant difference between yawn and control conditions. As no one has explicitly tested the performance of different controls against each other [44], we do not know whether any one control is better at eliciting baseline levels of yawning than any other (see [44] for a more in-depth discussion of controls used for studying CY). We inserted 1 s of green screen between each clip, and assembled them into a yawn video and a control for each class (yielding a total of six videos). Each clip was shown once before repeating the entire set, and the order within a set was randomized except that a clip could not be shown twice in a row.
Mean rate of yawning in each session by class and condition. The chimpanzees yawned significantly more when watching the yawn (black bars) than the control (white bars) videos for familiar humans (p = 0.025) and strange humans (p = 0.022), but the difference was non-significant for gelada baboons.
We calculated a yawning index for each individual by subtracting the number of yawns in the control sessions from the number of yawns in the yawn sessions for each class. The graph presents the mean differences + s.e.m. Data for ingroup and outgroup chimpanzees come from our earlier study [13] (grey bars). Previously, we studied 23 chimpanzees in 20 min sessions [13], and in this study (black bars) we worked with 19 chimpanzees in 10 min sessions. The data for [13] have been sampled and restricted to match the current parameters (the same 19 chimpanzees for 10 min), thus a side-by-side comparison with the graphs from [13] will not match. The response to familiar humans, strange humans and ingroup chimpanzees was significantly greater than the response to outgroup chimpanzees and gelada baboons (p = 0.003).
We found a difference in the yawning rate between stimuli that did and those that did not elicit contagion (figure 2). Among the three stimuli that elicited contagion (i.e. ingroup chimpanzees, familiar humans and unfamiliar humans), the yawning rates were similar and none of these stimuli was more potent than another. Thus, we did not observe different magnitudes of CY, in contrast to human studies in which the degree of contagion follows a continuum based on social closeness [12]. Either humans are more discriminating in their CY responses, or we have not yet designed the experiment in the right way for chimpanzees.
The different responses to the different stimuli further support the idea that CY is socially modulated, and thus serves as a measure of empathic engagement with the stimulus. As outgroup chimpanzees and gelada baboons did not stimulate significant rates of yawning, CY does not seem to be a simple fixed-action pattern for which any yawn may serve as a releaser. As for why humans but not gelada baboons stimulated contagion, physical resemblance or lack thereof probably does not alone account for the differences as outgroup chimpanzees did not stimulate CY. Rather, social experience probably plays a role. Would mere exposure to gelada baboons make them more familiar and lead to contagion? Or is mere exposure not enough and CY requires a history of positive social interactions, such as the chimpanzees have with most humans? Most interestingly, could experience change the way chimpanzees respond to outgroup chimpanzees? These are unanswered questions.
After the domestic month of January, primarily dedicated in the elephant seal world to the cows giving birth to and nursing their pups, February is a wild month for elephant seal bulls and the cows they are pursuing. The pursuit and the mating are neither delicate nor always mutually agreeable.
The resulting matings, both successful and unsuccessful, are sometimes difficult for visitors to watch, especially if they have spent the previous weeks witnessing cows nurse their ever-fattening and often vocalizing dark-furred pups.
Although statistics show that the peak of mating occurs right around Valentine's Day, there is nothing we humans would identify as romantic about the coupling. The whole interchange is rapid and can appear brutal to park visitors.
Peggy McCutcheon, longtime Winter Wildlife Docent, told of introducing her stepdaughter, Hannah Rouley Bowick, to the world of elephant seal mating. (Hannah went on to be a docent herself for several years.) As Peggy explained to Hannah on her first visit, "There is no wining and dining." Instead, as pioneering elephant seal expert Burney LeBoeuf described, "Male courtship is usually direct, aggressive and persistent." Peggy went a little further in her down-to-earth, unscientific description, "It almost seems like assault," she said, before acknowledging that she might be anthropomorphizing, or assigning human values and characteristics to the elephant seals.
As the video above (from which the still photo at the top of the article comes) shows, the bull moves directly to the side of the cow and, with no preliminaries, places his flipper over her back and bites her neck. He can leverage his considerable weight advantage, using his head and upper body to pin down a less-than-receptive cow, but even then, a bull is not always successful. The cow can and does resist by wriggling, vocalizing, and using her flipper to throw sand on the bull if she is not receptive to mating.
In addition, as Sue Van Der Wal, who has been a Point Reyes volunteer for decades, noted another aspect of the harshness of the whole mating process: "A bull, who can move at six miles per hour on land in a burst, can, without even knowing, crush or even kill a pup as he is pursuing a cow" or, as in this video below, trying to get away from the alpha male who is defending the beach. Pups getting killed is, however, mercifully rare!
Here's how delayed implantation works. When the cows copulate as they are finishing nursing their pups, often mating with multiple partners, their egg is fertilized. They are indeed technically pregnant with a fertilized blastocyst floating around in their uterus. But, because their bodies are so depleted, both from nursing their pups and from fasting, they need to bulk up again before the blastocyst implants and begins to develop. As a result, the blastocyst floats in the uterus for several months before implanting in the uterine wall and beginning development. So, though gestation lasts for 11 months, the actual development of the pup fetus occurs over seven months after the delayed implantation of the blastocyst into the uterine wall.
In all human populations, people usually select mates non-randomly for traits that are easily observable. Cultural values and social rules primarily guide mate selection. Most commonly, mating is with similar people in respect to traits such as skin color, stature, and personality. Animal breeders do essentially the same thing when they intentionally try to improve varieties or create new ones by carefully making sure that mating is not random. When they select mates for their animals based on desired traits, farmers hope to increase the frequency of those traits in future generations. In so far as the discriminated traits are genetically inherited, evolution is usually a consequence. However, the results are not always what farmers expect. The reasons why will be explained shortly.