We may think that gift giving is a purely human trait, but it turns out many other animals also treat their mates and companions.

我们可能认为送礼纯粹是一种人类的社交行为，但是事实证明许多其他动物也会送礼给它们的伴侣和同伴。

If on Christmas morning, upon opening your annual gift of novelty socks, your feeling is that of crushing disappointment, you can at least be thankful that you're not a female scorpionfly.

圣诞节早晨的礼物让你大失所望？往好处想想，至少你不是一只雌性褐蝇。

If you were, then the best you could look forward to at yuletide would be a ball of spit from the love of your life. Far from being disappointed though, female scorpionflies relish the tasty treat, rewarding their suitors with the opportunity to mate with them.

如果你是，那么圣诞节你所能期待的最好礼物就是爱“人”吐给你的一团口水。然而事实上，雌性褐蝇并不觉得失望，反而很享受这种美味的宽带，并奖励追求者交配的机会。

Nuptial gift giving – when the male presents the female with a nutritious morsel during courtship and mating – has been noted in species as diverse as snails, earthworms and squid. Birds have been known to enjoy gift giving too, with male great grey shrikes impaling small creatures on thorns and twigs to impress mates, before offering them as presents during courtship.

蜗牛、蚯蚓和鱿鱼等许多物种中都发现了送礼的行为——雄性在求偶和交配过程中会向雌性提供营养食物。众所周知，鸟类也喜欢送礼，雄性大灰伯劳鸟会把小动物刺在荆棘和树枝上给配偶留下深刻印象，然后在求偶期间作为礼物送给它们。

However, the phenomenon is most common amongst insects and arachnids. Male six-spot burnet moths, for example, give their female partners cyanide delivered via their sperm. Nursery web spiders, on the other hand, present potential mates with prey wrapped up in silk, with added chemicals to make it more attractive. If the female refuses, the male simply adds more wrapping to the gift, before offering it again. 

然而，这种现象在昆虫和蛛形纲动物中最为常见。例如，雄性六斑蛾会通过精子向雌性伴侣提供氰化物。另一方面，幼年网蛛会用包裹在丝线中的猎物送给潜在的伴侣，并添加一点能让猎物更有吸引力的气息。如果雌性拒绝了，雄性就会在这份礼物上多包几圈再送一次。

Sometimes the males try to trick the females by wrapping up low-quality prey, or even paltry half-consumed morsels. While the female is busy unwrapping what she thinks is a thoughtful gift, he'll mate with her and run off before she realises. One study found that as many as 70% of gifts given by male nursery web spiders are fake.

有时，雄性会试图通过包装低质量的猎物，甚至是已经被吃掉一半的猎物来欺骗雌性。当雌性打开那份她认为是贴心的礼物的时候，雄性就会抓住机会与之进行交配，并在雌性意识到礼物的偷工减料之前就跑掉。一项研究发现，雄性幼蛛所赠送的礼物中有高达70%的假货。

"You do get males attempting to cheat. They might wrap up an old, dried-up leg of a cricket, or something," says Darryl Gwynne, a behavioural ecologist at the University of Toronto in Canada.

加拿大多伦多大学的行为生态学家Darryl Gwynne说：“确实能抓到雄性试图作弊的行为。它们有时候会把一条干涸的蟋蟀腿或是别的什么东西包起来。”

Other insects have been known to try to skimp on gifts too.

还有些其他昆虫也有敷衍送礼的行为。

"Down the road from my house in spring there's a really beautiful thing where male dance flies go out over the river and catch aquatic insects," says Gwynne.

"They bring it back, and females compete for the prey because they can't feed themselves, and they need this nutrition to produce their eggs. On one occasion, I saw a male come in with a ball of willow fluff that comes off the willow seed and attempt to present that."

“春天，在我回家的路上会发生一件非常美丽的事情，雄性舞蝇会飞到河对岸捕捉水生昆虫。”Gwynne说道，“它们会把昆虫带回来，雌性则会竞争这些猎物，因为它们无法自己养活自己，而它们需要这些营养来产卵。有一次，我看到一只雄性带着从柳树籽上脱落的柳树绒毛球回来，企图把它当成礼物来送。”

In 2022, entomologist Chufei Tang of China's Jiangsu Academy of Agricultural Sciences and her colleagues even uncovered an example of insect gift-giving preserved in 99-million-year-old amber. Inside the ancient amber, a male fly of the genus Alavesia grasps an empty, frothy balloon made of mucus between his legs.

2022年，中国江苏省农业科学院昆虫学家唐楚飞和她的同事们甚至发现了一个保存在9900万年前琥珀中的昆虫送礼的例子。在这块古老的琥珀中，一只Alavesia属的雄性苍蝇在腿间夹了一个由粘液制成的空的泡沫气球。

All these examples are nuptial gifts, given by males to females to convince them to mate. More often than not, these gifts have a nutritional value, so the female benefits too. However sometimes animals have been known to give presents just to please the recipient. For example, dolphins have been observed giving food to people, with offerings including eels, tuna and octopuses. There are also accounts of crows giving presents to humans that have helped them in the past.

以上这些例子都是男性给女性送的“新婚”礼物以说服它们进行交配。通常情况下，这些礼物具有营养价值，使得雌性从中受益。然而，有时动物会为了取悦接受者而送礼。例如，人们观察到海豚向人类投食的行为，所提供的食物包括鳗鱼、金枪鱼和章鱼。也有关于乌鸦给人类送礼物的记载，这些接收礼物的人曾在过去帮助过它们。

"I've received gifts from crows including walnuts, olives, bottle tops from beer bottles, and wine corks," says Nicola Clayton, professor of comparative cognition at the University of Cambridge in the UK.

英国剑桥大学比较认知学教授Nicola Clayton就表示他曾收到过乌鸦的礼物，包括核桃、橄榄、啤酒瓶的瓶盖和葡萄酒瓶的瓶塞。

Eurasian jays, which are members of the crow family, also appear to give gifts to their mates simply for the joy of giving. In one experiment by Clayton and her team, males watched their mates eating either moths or worms. When given the opportunity to give his partner a juicy morsel, the male consistently chose to give his mate the different food. In other words, the males understood that the females would rather have something new than more of the same.

欧亚松鸦，乌鸦科中的一种，似乎也只是为了乐趣而给伴侣赠送礼物。在Clayton和她团队的一项实验中，雄性会看着它们的伴侣吃飞蛾或蠕虫。当它们发现有机会可以给伴侣提供更多食物时，它们总是选择投喂不同种类的食物。换句话说。雄性明白雌性更希望有新的选择而不是拥有更多相同的东西。

"It's like if you're out to dinner and you've just had a nice spaghetti bolognese," says Clayton. "If somebody said, 'Do you want another one? 'You'd say, 'No thank you.' But you can manage to find room for a dessert. The jays seemed to know what their partners wanted and could give the right kind of present

“这就像你出去吃饭，刚刚吃了一顿美味的意大利肉酱面，”克莱顿说，“如果有人问‘你想要再来一份吗’你会说，‘不用了，谢谢。’但你可以设法找个地方再来一份甜点。”松鸦似乎知道他们的伴侣想要什么，知道送什么礼物是合适的。

So, this all begs the question – why do animals give each other gifts? As the behaviour has evolved multiple times across different species, it likely enhances the reproductive fitness of both males and females. This is certainly true in the case of insects and arachnids – except when one party cheats.

那么，这一切都引出了一个问题——为什么动物会互相赠送礼物？由于这种行为在不同物种中已经进化了多次，它可能是为了增强雄性和雌性的繁衍成功率。对于昆虫和蛛形纲动物来说这个推论肯定是没错的——除非一方作弊。

But if this doesn't sound particularly romantic, you can take heart from the fact that other animals, such as crows and bonobos, also appear to take pleasure from the simple act of giving.

如果你觉得这个解释不够浪漫，也可以看看诸如乌鸦和倭黑猩猩，它们会从简单的给予行为中获得快乐。

"In the insect world the male gives the gift so he can mate with the female, but in the jays they pair for life, so it's not it's not a bribe, it's a gift," says Clayton.

克莱顿说道：“在昆虫世界里，雄性会送礼物以获得交配权。但松鸦是终生配对制的，因此这并不是一种贿赂，而是礼物。”

"Jays are highly intelligent, long-lived animals, and as you know, attaining a relationship is one thing, but maintaining it over many years is much harder. So gifts are a token of appreciation."

“鸟类是非常聪明、长寿的动物，如你所知，建立关系是一回事，但是要维持长久的关系则困难的多。所以礼物是一种感谢的象征。”