Por que os olhos dos gatos brilham no escuro?

Por: Professor Leandro Sinis

Quando uma luz atinge os olhos de um gato no escuro, eles podem parecer brilhantes. Mas o animal não produz luz: ele apenas a reflete.

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O responsável pelo efeito é o tapete lúcido, uma estrutura localizada atrás da retina que ajuda a aproveitar melhor a pouca luz disponível.

[{"selector":"#anim-b652d2c0-26de-4b9b-9974-b20ab5d410c5 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(0%, 0, 0) translate(25%, 0%) scale(1.5)","translate3d(0%, 0, 0) translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"fill":"forwards"}] [{"selector":"#anim-2e11c935-262b-4e1c-a2de-6a75c4f7ea0e","keyframes":{"transform":["translate3d(-115.18988%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-b0b74183-e275-45d3-bb0c-a1c481fb5cb9","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-30191a53-80d3-45b1-9e65-ec88b652b1e7","keyframes":{"transform":["scale(0.15)","scale(1)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"forwards"}] Existe uma estrutura especial

O tapete lúcido reflete parte da luz que atravessou a retina, fazendo com que ela passe novamente pelas células sensíveis à luminosidade.

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Essa reflexão aumenta as oportunidades de os fotorreceptores captarem luz. Por isso, gatos conseguem se orientar melhor em ambientes pouco iluminados.

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Quando uma lanterna ou outra fonte ilumina um gato no escuro, parte da luz refletida pelo tapete lúcido retorna em nossa direção.

[{"selector":"#anim-41c58a41-0c3c-4712-b56f-46737e3f89ef [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(0%, 0, 0) translate(25%, 0%) scale(1.5)","translate3d(0%, 0, 0) translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"fill":"forwards"}] [{"selector":"#anim-d82adcce-23d1-4b47-bc8f-20dfbb713cde","keyframes":{"transform":["translate3d(-115.18988%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-79dc4b57-9787-4f4c-8892-eb4e32e448f7","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-7470a8d7-0430-47ab-826d-cfa70620714a","keyframes":{"transform":["scale(0.15)","scale(1)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"forwards"}] E é daí que surge o brilho

A aparência do reflexo pode variar entre gatos. Fatores como a estrutura ocular, a idade e o ângulo da luz influenciam o efeito observado.

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Mesmo com essa adaptação, gatos não conseguem formar imagens na ausência total de luz. O tapete lúcido apenas ajuda a aproveitar melhor a existente.

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A pupila felina muda bastante de tamanho conforme a iluminação. Em ambientes escuros, ela se dilata para permitir a entrada de mais luz.

[{"selector":"#anim-94f22d9d-3da6-4eb0-91f1-81a6ea7ee57e [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(0%, 0, 0) translate(25%, 0%) scale(1.5)","translate3d(0%, 0, 0) translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"fill":"forwards"}] [{"selector":"#anim-1a95d0a4-6222-4f97-801c-b08ca3e79e03","keyframes":{"transform":["translate3d(-115.18988%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-b8eefb97-b58b-4c54-bffe-15361b8b79af","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-cf04376e-0402-4c6b-ac71-3cbb7bd4a2cb","keyframes":{"transform":["scale(0.15)","scale(1)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"forwards"}] A pupila também ajuda

O famoso brilho dos olhos é consequência de um sistema visual adaptado à baixa luminosidade, que ajuda o gato a aproveitar cada pequena quantidade de luz.

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[{"selector":"#anim-9687552e-db69-4ab6-a897-56969348f486","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-c5951057-b8d9-47f5-bd32-5c6cb6df4436","keyframes":{"transform":["translate3d(-122.07206%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-ad41a9e7-4d45-4b2c-a26f-704e323d26bb","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-445dd861-a38c-4d31-9fc3-69cb22e06a32","keyframes":{"transform":["translate3d(-189.44723%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] Veja Mais: O mundo pelos olhos de cães e gatos é bem diferente do que imaginamos